The O2 is empty and there are no more coins left to put in the meter, which means we must wrap up this live text commentary. There will be more from us this evening, however, as Stan Wawrinka takes on Marin Cilic at 20:00 GMT. Thanks, as always, for your contributions. Bye for now.
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John McEnroe, who has joined Sue Barker and Tim Henman, in the studio, is full of praise for Nishikori.
"I don't understand these big guys. Nishikori, mentally he's so strong right now, he's giving you different looks, he came to the net, hit some serve volleys - memos to other top players who are six inches bigger than him."
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Novak Djokovic and Kei Nishikori have played each other on four occasions, with both enjoying two victories each. Nishikori, of court, surprised many by beating the world number one at this year's US Open semi-finals.
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John McEnroe on ending the year as world number one: "For me, it meant more than the Slams. In retrospect I sort of wished I'd taken the Slams more seriously. I took great pride in that (ending the year as world number one). One year, I finished number one but didn't win any majors. It's not that easy to finish number one, regardless if you win a Slam or not."
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Tim Henman
Former British number one on BBC Two
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"When you're playing indoors with perfect elements, they can elevate their games. Some of the tennis we've seen from those two (Djokovic and Federer) has been as good as I've ever seen. I'm keeping my fingers crossed we see Federer versus Djokovic in the final, that would be a fitting end."
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Denise in Wiltshire: It's such a shame how so many people are so quick to slate Andy Murray when he loses a match. I wonder if this these are the same people who voted him Sports Personality Of The Year In 2013.
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We've also been asking you this afternoon how Andy Murray should react after last night's defeat:
Phil: Murray shouldn't panic. Fed struggled last year & has bounced back superbly. Add some variety & net play to an already solid game.
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Tim Henman
Former British number one on BBC Two
On TV, the chat has returned to Murray. Here's what Henman has to say:
"It will be an interesting off season. He's talked about getting a super coach involved. I thought Mats Wilander, at once stage, would be a good addition. It'll be interesting to see if he can add another dynamic to his game next year."
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Djokovic poses for the cameras after exchanging handshakes and backslaps with the likes of McEnroe. The photographers don't have to ask him to smile.
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Djokovic has yet to be beaten since becoming a father to baby Stefan on 22 October.
"I got married, became a father recently and it's the most beautiful thing in the world and to be able to stand next to this trophy and to have the crown for all the achievements in this 12 months, it's very fulfilling and it's a joy," says Djokovic.
Asked if he will celebrate this evening, Djokovic replies: "I don't think so, the tournament is not over. I have maybe a few hours of celebration and then turning back to semi finals and preparing for it."
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The man of the moment, Djokovic, jumps up from his chair but is being made to watch a video montage of his year while the big-eared silver trophy twinkles in the spotlight in front of him.
Finally, the world number one is allowed to take his prize and he lifts it skywards, kissing the sought-after silverware.
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Tournament organiser Chris Kermode steps onto the court to present Novak Djokovic with the year-end world number one trophy. There are also special guests, it's a bit like Surprise Surprise, as John McEnroe, Boris Becker and Mats Wilander appear.
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"Definitely one of the best," says Djokovic of his performance. "Obviously I hoped I could continue the way I played in the first two matches. It's been a long year, a long season, it's an incredible achievement and I want to thank my team and my family and all the people who supported me.
"I'm aware that being number one in the world is the biggest challenges a tennis player can have. It's an incredible feeling and I'm very happy.
"I've been playing since I was four. I was very fortunate to have very knowledgably people, the people who believed in me and believed in my talent."
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After the first game of the first set, when he broke Berdych, it felt almost inevitable that Djokovic would win, and do so comfortably. Djokovic's semi-final opponent? Kei Nishikori. "It won't be easy," says Djokovic.
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Tim Henman
Former British number one on BBC Two
(when asked what Kei Nishikori's tactics should be if he wants to beat Djokovic in the semi-finals)
"I'd be looking at food poisoning first..."
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Andrew Castle
BBC tennis commentator on BBC Two
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"The celebration is for the year-ending number one position. It's like winning the league, and it's the result of a lifetime's work for him and his team. A tremendous sporting achievement."
Game, set and match
Djokovic 6-2 6-2 Berdych
Here we go. The final game of the match. The two-time defending champion closing in on his 30th consecutive victory indoors. He pulls Berdych this way and that from the baseline, the bedraggled Czech unable to negotiate the barrier and Djokovic has three match points. He needs just the one - Berdych wide. Djokovic undefeated in this tournament, dropping just nine games in three matches, and he will end the year as world number one.
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*Djokovic 6-2 5-2 Berdych
At 30-0 the pair trade blows from the baseline, with Djokovic pulling the trigger with a jaw-droppingly good backhand winner down the line. The Serb pulls Berdych towards the net with a drop shot - but Berdych covers the ground quickly, gently volleying beyond the Serb to hold to 15.
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Andrew Castle
BBC tennis commentator on BBC Two
"For Djokovic, to have lost only five games in his first two matches against Cilic and Wawrinka is amazing. He's a game away from another milestone."
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Djokovic 6-2 5-1 Berdych*
Berdych's feet aren't moving in unison and the 6ft 5in Czech looks flat-footed on the baseline. Another simple hold for Djokovic, concluding with a cool ace. The Serb clenches his fists, he knows victory is in sight.
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Bernard Clayton: Surely this has to have been one of the worst tournaments ever. Only one match has gone to three sets and a ridiculous number of matches over in less than an hour. But why? This will not encourage people to apply for tickets next year.
Al, Cambridge: The gulf between the top three and the rest is big right now. And it's been a weird week. By today, 10 of 21 sets were 6-1 or worse. Unusual for men's game.
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Tom Carr: I always thought Murray was leaning towards McEnroe when he was looking for a new coach, but he should see how Aus Open goes.
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*Djokovic 6-2 4-1 Berdych
Applause from the crowd as Djokovic comes out on top of a baseline rally thanks to a bullet of a forehand down the line. The world number one collecting points with ease, though Berdych levels from 15-30 to 30-30 thanks to a punchy serve. An overcooked Berdych backhand... groans from the crowd... and they start to slow clap as Berdych attempts to regain composure to save a break point.
The pair battle it out from the baseline, going from side to side, and, surprisingly, it's Djokovic who crumbles like a chocolate flake. On the next point, the Serb is pushed out wide by some big hitting from Berdych and even the game's greatest retriever has to occasionally wave the wide flag. Berdych at advantage, then deuce, then advantage, before finally holding as Djokovic nets.
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Andrew Castle
BBC tennis commentator on BBC Two
"Berdych needs to get the scoreboard rolling in this second set - and break the hour mark for this match."
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Dino Vlachopoulos: This week you almost get the impression players other than Federer and Djokovic are amateurs.
SportsFan: Must be great to play tennis with the feeling that you are not going to miss. Mortals can dream!
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Djokovic 6-2 4-0 Berdych*
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A serve out wide, Berdych goes the wrong way, Djokovic follows up with a textbook volley. Simple but effective by the Serb. "Come on," Djokovic whispers to himself as he bamboozles Berdych with an ace and, without fuss or drama, Djokovic secures a straightforward hold - Berdych long on the return.
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We've also been asking you how you think Andy Murray can improve after last night:
Adrian Ham: Sad about Murray. First he needs to get back to 2008-mid 2012 level when he was a whisker off the big three and well clear of rest.
Andrew Neill: Murray needs to hire someone like Sampras who not only has the experience he needs but can sort his serve out. It needs it!
Chris Roberts: Hire Lendl again. Never been the same since they parted ways.
Djokovic breaks
*Djokovic 6-2 3-0 Berdych
Dreamy from Djokovic, just dreamy, as he slides along the baseline, trainers screeching, limbs at full stretch, and produces a peach of a crosscourt winner. Berdych in danger once more. 15-30: cue "Jaws" music. Der-dum... Der-dum...
Djokovic sinks his teeth into his opponent from the baseline, forcing the Czech to overcook a forehand. Two break points Djokovic. A botched Berdych backhand and it's all over. Berdych looks at his racquet, but his strings aren't speaking to him at the moment.
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Andrew Castle
BBC tennis commentator on BBC Two
"At various times over his career, Djokovic has taken on other people to help work on his game - Todd Martin and Mark Woodforde among them. I'm not sure the Todd Martin episode worked, but Mark Woodforde is a tremendous coach."
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Djokovic 6-2 2-0 Berdych*
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Every point for Berdych must feel like a long, tortuous trek up Kilimanjaro. The 29-year-old Czech nicks one point on the Djokovic serve, but the majority of his returns plonk into the net, allowing the Serb to ease to a hold to 15. Is there a way back from here for Berdych.
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Andrew Castle
BBC tennis commentator on BBC Two
"When Djokovic is winning this easily, the only thing he has to guard against is complacency. But with the semi-finals tomorrow, the quicker he can get off court, the better."
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Angus in London: I have been watching Andy Murray since he began and never remember anything like last night. His mental resolve shot, nothing to offer in response and huge unforced errors. It's been a tough year though and he will bounce back. Solid fitness and more matches make a huge difference. I'm still undecided if he needs a new coach - wait until after Australia? No coach could have helped him last night!
Djokovic breaks
Djokovic 6-2 1-0 Berdych
A promising start for Berdych. An ace down the middle to advance to 30-0... Another easy point... 40-0... the Czech cruising...
But he misfires on the next point, a forehand wide for 40-15, and double faults on the next. Oh my. Danger. Djokovic drags his opponent to deuce. Unforced errors proving to be Berdych's downfall.
Advantage. Deuce. A fruitful start turning into a messy end for Berdych, who slaps an easy forehand into the tape to gift Djokovic a break point.
An ace from Berdych saves the day - or does it? Djokovic challenges and the Serb, who has 20/20 vision is seems, is proved right. Still break point Djokovic... Berdych on the backfoot at the baseline... the Czech's forehand drifts wide. Djokovic bossing it.
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Tim Henman
Former British number one on BBC Two
"Berdych has a very good game, but I'd like to see him add more strings to his bow. He needs to try something different against Djokovic - what's he got to lose? It's not like he's going to come third. He's 6ft 5ins, his second serve is 88mph - and he hits it straight up the middle of the court back to Djokovic."
John McEnerney: ND wants to do what Fed did to AM & he's all about business as usual, super clinical. He's in great form & unstoppable even 4 Fed.
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Andrew Castle
BBC tennis commentator on BBC Two
"That's Djokovic definitely through to the semi-finals. We'll be seeing him on Saturday... and most probably Sunday too."
Game and first set
Djokovic 6-2 Berdych*
The Djokovic backhand is purring, the world number one making Berdych look as if he has cement in his boots as he drills one into the corner for the first point.
A bit of fortune for Berdych, though, and the big Czech raises his racquet in acknowledgement as a mishit lob drops inside the baseline.
That is as good as it gets for the 29-year-old, though, as Djokovic accumulates two break points, needing just the one - Berdych returning long - to hold to 15.
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Andrew Castle
BBC tennis commentator on BBC Two
"Reaching the final of Wimbledon in 2010 was probably Berdych's career highlight. But he lost to Cilic in two of the Grand Slams this year. He's a consistent performer, but how do you turn him into a Grand Slam winner?"
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Sanj: #ATPFinals really should've been Djokovic v Federer every day. Guy with most wins in week gets the trophy. That would've been fun!
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Sue in Northampton: I saw Lendl win this in '85 from my hospital bed - am I right in saying his prize was a diamond studded racket?
Daniel Jellicoe: Quite simply the one thing Murray lacks is a big first serve, something Federer and Djokovic both possess. He needs to win more free points.
Please remember to put your name on your texts.
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*Djokovic 5-2 Berdych
What's happening here? Berdych wins two points on the trot to ease 30-0 ahead. The Czech in unchartered territory, never has he had such a handsome lead in this set.
Another faulty return from Djokovic, into the tramlines his forehand goes, and the Serb looks skywards and gives out a slight groan. The world number one has had little to grumble about in this set, though. It's a hold to 30 for Berdych, the Czech finding form but it's (probably) a little too late, for this set at least.
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Andrew Castle
BBC tennis commentator on BBC Two
"Three first serves in a row from 15-30 make it 5-1. You can't attack him."
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Djokovic 5-1 Berdych*
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Oof! A splendid serve from Djokovic, full of spin and menace - Berdych unable to do anything other than direct it towards Boris Becker in the front row. Boris throws the ball back onto the court. I guess he doesn't need any tennis mementos.
A routine hold from the Serb, his first serve on song, as is the rest of his game to be honest.
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Stephanie Siu: Such is the allure of the BBC live feed that I'm sitting in the O2 with my bro & he's reading the feed over watching the action!
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*Djokovic 4-1 Berdych
An intake of breath from the spectators as they admiringly watch Djokovic on the run, turning defence into attack with a rasping crosscourt forehand winner.
A Berdych point! 17,000 spectators are whooping and whistling as the Czech produces an overhead at the net, eating into Djokoivc's lead. 15-30. Berdych then follows up with a snazzy ace to level at 30-30 and the Czech has some sort of momentum, pulling through to hold.
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Djokovic 4-0 Berdych*
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If Djokovic reaches the semi-final with a 3-0 record in the round-robin matches, he will be guaranteed to end the year as world number one regardless of what Federer does at this tournament and the Davis Cup final. It feels as if we're heading for a routine Djokovic victory because the Serb is eye-wateringly good - feather-soft touches at the net for a hold to love.
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Robert Allen: I wonder if all these people busy writing Murray off, were the ones who said he'd never win one Grand Slam, let alone two!
Mark Farman: Andy needs to be more aggressive and punish his opponents, if his game matched his temperament he'd be number one in the world.
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Carl Keegan: Well, three games in, that just about wraps it up for Berdych.
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Andrew Castle
BBC tennis commentator on BBC Two
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"Does Berdych has anything else in his game he can actually go to?"
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Tim Henman
Former British number one on BBC Two
"Another relevant tactic against Djokovic is mixing up your speed of serve. The harder you serve, the harder it comes back!"
Djokovic breaks
*Djokovic 3-0 Berdych
Berdych out of his comfort zone, dashing to the net, but his crosscourt volley drifts into the tramlines and Djokovic is ahead once again. From 15-30 to 15-40... two break points Djokovic... the crowd slow clap... Berdych shrugs his shoulders, looks towards his camp for answers...
Djokovic screws a return wide. One break point saved. Is there hope? Oh, deary me, the Czech is wide, wide, wide and Djokovic breaks once again.
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Tim Henman
Former British number one on BBC Two
"It's obviously early days in this match, but Berdych has to know that this style of play doesn't work. Are we going to see him change anything? Come to the net occasionally? On the baseline, there's only going to be one winner."
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Djokovic 2-0 Berdych*
At 30-0 Djokovic goes long and the crowd heartily applaud as Berdych wins his first point of the match. Hoorah! A double fault from Djokovic for 30-30, but for some reason it doesn't feel as if the Serb's dominance will be threatened. He launches a boomer of an ace to skip 40-30 ahead and the game ends with the familiar sight of Berdych failing to negotiate the barrier.
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James Alex: I don't think Murray will win a Grand Slam again, Nishikori and Dimitrov coming up fast now. Someone like McEnroe, Wilander, Agassi, Sampras is what Murray needs, a proven Grand Slam champion.
"We saw a masterclass from Roger Federer last night, but we could see another one from Novak Djokovic. He just seems to get better and better."
Djokovic break
*Djokovic 1-0 Berdych
The story of this match begins with Djokovic nicking the opening point before proceeding to a 0-30 lead after coming out on top of a baseline tussle. Deep breaths from the Serb, who is quickly back in position and returning brilliantly.
The net must seem like a 10ft wall for Berdych as Djokovic collects three break points and breaks thanks to a stonking backhand return. Impressive stuff from the world number one.
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Tim Henman
Former British number one on BBC Two
"With this being Berdych's last match of the year, you just want him to come out and see if he can make life uncomfortable for Djokovic."
Djokovic on top of the world
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One victory - that's all Djokovic needs to ensure he end the year as the world number one. Should he achieve that feat he will join Pete Sampras, Roger Federer, Jimmy Connors, Ivan Lendl, John McEnroe and Rafael Nadal on the list of players who have finished year-end world number ones for three seasons.
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Andrew Castle
BBC tennis commentator on BBC Two
"Has Murray got the right person in his corner with Amelie Mauresmo? That's not a criticism - but I think I would be feeling a bit vulnerable if I was her. I might be getting on the phone to Ivan [Lendl] and asking 'are you sure you're not free next year?'"
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It's time to now focus on this afternoon's match because Djokovic and Berdych have strolled through the dry ice to a warm welcome and are currently warming up, while Tim Henman and Andrew Castle chat about Murray's future.
By the way, you can watch Sue and co by clicking the 'live coverage' tab on this page. There is also live coverage on BBC Radio 5 live sports extra.
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Andrew Castle
BBC tennis commentator on BBC Two
"I think what happened last night was a sporting aberration. Murray was dismissed by possibly the greatest player of all time, in full flow. Murray has played well in the last few weeks, but how's he going to compete with Nadal when he comes back, with Djokovic, and with Roger? At the age of 27, does he want to remodel his game? I think minor changes are necessary."
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What should Murray do next and where does he need to improve? Can he challenge the top three next season? You can either tweet us your thoughts using the hashtag #bbctennis, text 81111 or visit theBBC Sport Facebook page. It'll be nice to hear from you.
Special One gives Murray advice
Jose Mourinho was at the O2 last night to watch Federer gracefully progress to the semi-finals, and the Chelsea boss has some advice for Murray.
"There are some matches where we feel it's not our day and I think that applies to football and any other sport, even in tennis," said the Portuguese.
"But in all, pride, and play for the people that are behind him and even if he knows that it is very difficult to beat Roger tonight, give his best and sometimes a bad defeat is the beginning of many, many victories and hopefully next season will be a much better season for Andy."
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Tim Henman
Former British number one on BBC Two
"Federer was exceptional, but Andy was given a thumping, it's not the way he would want to finish his season."
Defeat hurts - Murray
Talking of crushing defeats... "Exceptional" is how Andy Murray described Roger Federer's performance during the world number two's 6-0 6-1 thrashing of the British number one last night.
"This year has been testing and I've learned a lot along the way, it's just a shame to finish it with another very harsh lesson. I'm sure it will be a tough one to look back in the future."
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Hello! Welcome to live text coverage of the last two ATP World Tour Finals round-robin matches, starting with Novak Djokovic's ding-dong with Tomas Berdych. If the rest of the week is a guide to how this afternoon's match will unfold we can expect one player (probably Djokovic) to crush the other (probably Berdych) in a straight-sets defeat, but funny things can happen at the O2.
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One person's dream is another's nightmare. A week of annihilations and humiliations is about to come to an end but, worry not, there's will be more suffering and conquering before the week is out.
Live Reporting
Aimee Lewis
All times stated are UK
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Latest PostPost update
The O2 is empty and there are no more coins left to put in the meter, which means we must wrap up this live text commentary. There will be more from us this evening, however, as Stan Wawrinka takes on Marin Cilic at 20:00 GMT. Thanks, as always, for your contributions. Bye for now.
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John McEnroe, who has joined Sue Barker and Tim Henman, in the studio, is full of praise for Nishikori.
"I don't understand these big guys. Nishikori, mentally he's so strong right now, he's giving you different looks, he came to the net, hit some serve volleys - memos to other top players who are six inches bigger than him."
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Novak Djokovic and Kei Nishikori have played each other on four occasions, with both enjoying two victories each. Nishikori, of court, surprised many by beating the world number one at this year's US Open semi-finals.
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John McEnroe on ending the year as world number one: "For me, it meant more than the Slams. In retrospect I sort of wished I'd taken the Slams more seriously. I took great pride in that (ending the year as world number one). One year, I finished number one but didn't win any majors. It's not that easy to finish number one, regardless if you win a Slam or not."
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Tim Henman
Former British number one on BBC Two
"When you're playing indoors with perfect elements, they can elevate their games. Some of the tennis we've seen from those two (Djokovic and Federer) has been as good as I've ever seen. I'm keeping my fingers crossed we see Federer versus Djokovic in the final, that would be a fitting end."
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Denise in Wiltshire: It's such a shame how so many people are so quick to slate Andy Murray when he loses a match. I wonder if this these are the same people who voted him Sports Personality Of The Year In 2013.
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We've also been asking you this afternoon how Andy Murray should react after last night's defeat:
Phil: Murray shouldn't panic. Fed struggled last year & has bounced back superbly. Add some variety & net play to an already solid game.
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Tim Henman
Former British number one on BBC Two
On TV, the chat has returned to Murray. Here's what Henman has to say:
"It will be an interesting off season. He's talked about getting a super coach involved. I thought Mats Wilander, at once stage, would be a good addition. It'll be interesting to see if he can add another dynamic to his game next year."
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Djokovic poses for the cameras after exchanging handshakes and backslaps with the likes of McEnroe. The photographers don't have to ask him to smile.
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Djokovic has yet to be beaten since becoming a father to baby Stefan on 22 October.
"I got married, became a father recently and it's the most beautiful thing in the world and to be able to stand next to this trophy and to have the crown for all the achievements in this 12 months, it's very fulfilling and it's a joy," says Djokovic.
Asked if he will celebrate this evening, Djokovic replies: "I don't think so, the tournament is not over. I have maybe a few hours of celebration and then turning back to semi finals and preparing for it."
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The man of the moment, Djokovic, jumps up from his chair but is being made to watch a video montage of his year while the big-eared silver trophy twinkles in the spotlight in front of him.
Finally, the world number one is allowed to take his prize and he lifts it skywards, kissing the sought-after silverware.
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Tournament organiser Chris Kermode steps onto the court to present Novak Djokovic with the year-end world number one trophy. There are also special guests, it's a bit like Surprise Surprise, as John McEnroe, Boris Becker and Mats Wilander appear.
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"Definitely one of the best," says Djokovic of his performance. "Obviously I hoped I could continue the way I played in the first two matches. It's been a long year, a long season, it's an incredible achievement and I want to thank my team and my family and all the people who supported me.
"I'm aware that being number one in the world is the biggest challenges a tennis player can have. It's an incredible feeling and I'm very happy.
"I've been playing since I was four. I was very fortunate to have very knowledgably people, the people who believed in me and believed in my talent."
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After the first game of the first set, when he broke Berdych, it felt almost inevitable that Djokovic would win, and do so comfortably. Djokovic's semi-final opponent? Kei Nishikori. "It won't be easy," says Djokovic.
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Tim Henman
Former British number one on BBC Two
(when asked what Kei Nishikori's tactics should be if he wants to beat Djokovic in the semi-finals)
"I'd be looking at food poisoning first..."
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Andrew Castle
BBC tennis commentator on BBC Two
"The celebration is for the year-ending number one position. It's like winning the league, and it's the result of a lifetime's work for him and his team. A tremendous sporting achievement."
Game, set and match
Djokovic 6-2 6-2 Berdych
Here we go. The final game of the match. The two-time defending champion closing in on his 30th consecutive victory indoors. He pulls Berdych this way and that from the baseline, the bedraggled Czech unable to negotiate the barrier and Djokovic has three match points. He needs just the one - Berdych wide. Djokovic undefeated in this tournament, dropping just nine games in three matches, and he will end the year as world number one.
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*Djokovic 6-2 5-2 Berdych
At 30-0 the pair trade blows from the baseline, with Djokovic pulling the trigger with a jaw-droppingly good backhand winner down the line. The Serb pulls Berdych towards the net with a drop shot - but Berdych covers the ground quickly, gently volleying beyond the Serb to hold to 15.
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Andrew Castle
BBC tennis commentator on BBC Two
"For Djokovic, to have lost only five games in his first two matches against Cilic and Wawrinka is amazing. He's a game away from another milestone."
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Djokovic 6-2 5-1 Berdych*
Berdych's feet aren't moving in unison and the 6ft 5in Czech looks flat-footed on the baseline. Another simple hold for Djokovic, concluding with a cool ace. The Serb clenches his fists, he knows victory is in sight.
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Bernard Clayton: Surely this has to have been one of the worst tournaments ever. Only one match has gone to three sets and a ridiculous number of matches over in less than an hour. But why? This will not encourage people to apply for tickets next year.
Al, Cambridge: The gulf between the top three and the rest is big right now. And it's been a weird week. By today, 10 of 21 sets were 6-1 or worse. Unusual for men's game.
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Tom Carr: I always thought Murray was leaning towards McEnroe when he was looking for a new coach, but he should see how Aus Open goes.
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*Djokovic 6-2 4-1 Berdych
Applause from the crowd as Djokovic comes out on top of a baseline rally thanks to a bullet of a forehand down the line. The world number one collecting points with ease, though Berdych levels from 15-30 to 30-30 thanks to a punchy serve. An overcooked Berdych backhand... groans from the crowd... and they start to slow clap as Berdych attempts to regain composure to save a break point.
The pair battle it out from the baseline, going from side to side, and, surprisingly, it's Djokovic who crumbles like a chocolate flake. On the next point, the Serb is pushed out wide by some big hitting from Berdych and even the game's greatest retriever has to occasionally wave the wide flag. Berdych at advantage, then deuce, then advantage, before finally holding as Djokovic nets.
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Andrew Castle
BBC tennis commentator on BBC Two
"Berdych needs to get the scoreboard rolling in this second set - and break the hour mark for this match."
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Dino Vlachopoulos: This week you almost get the impression players other than Federer and Djokovic are amateurs.
SportsFan: Must be great to play tennis with the feeling that you are not going to miss. Mortals can dream!
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Djokovic 6-2 4-0 Berdych*
A serve out wide, Berdych goes the wrong way, Djokovic follows up with a textbook volley. Simple but effective by the Serb. "Come on," Djokovic whispers to himself as he bamboozles Berdych with an ace and, without fuss or drama, Djokovic secures a straightforward hold - Berdych long on the return.
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We've also been asking you how you think Andy Murray can improve after last night:
Adrian Ham: Sad about Murray. First he needs to get back to 2008-mid 2012 level when he was a whisker off the big three and well clear of rest.
Andrew Neill: Murray needs to hire someone like Sampras who not only has the experience he needs but can sort his serve out. It needs it!
Chris Roberts: Hire Lendl again. Never been the same since they parted ways.
Djokovic breaks
*Djokovic 6-2 3-0 Berdych
Dreamy from Djokovic, just dreamy, as he slides along the baseline, trainers screeching, limbs at full stretch, and produces a peach of a crosscourt winner. Berdych in danger once more. 15-30: cue "Jaws" music. Der-dum... Der-dum...
Djokovic sinks his teeth into his opponent from the baseline, forcing the Czech to overcook a forehand. Two break points Djokovic. A botched Berdych backhand and it's all over. Berdych looks at his racquet, but his strings aren't speaking to him at the moment.
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Andrew Castle
BBC tennis commentator on BBC Two
"At various times over his career, Djokovic has taken on other people to help work on his game - Todd Martin and Mark Woodforde among them. I'm not sure the Todd Martin episode worked, but Mark Woodforde is a tremendous coach."
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Djokovic 6-2 2-0 Berdych*
Every point for Berdych must feel like a long, tortuous trek up Kilimanjaro. The 29-year-old Czech nicks one point on the Djokovic serve, but the majority of his returns plonk into the net, allowing the Serb to ease to a hold to 15. Is there a way back from here for Berdych.
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Andrew Castle
BBC tennis commentator on BBC Two
"When Djokovic is winning this easily, the only thing he has to guard against is complacency. But with the semi-finals tomorrow, the quicker he can get off court, the better."
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Angus in London: I have been watching Andy Murray since he began and never remember anything like last night. His mental resolve shot, nothing to offer in response and huge unforced errors. It's been a tough year though and he will bounce back. Solid fitness and more matches make a huge difference. I'm still undecided if he needs a new coach - wait until after Australia? No coach could have helped him last night!
Djokovic breaks
Djokovic 6-2 1-0 Berdych
A promising start for Berdych. An ace down the middle to advance to 30-0... Another easy point... 40-0... the Czech cruising...
But he misfires on the next point, a forehand wide for 40-15, and double faults on the next. Oh my. Danger. Djokovic drags his opponent to deuce. Unforced errors proving to be Berdych's downfall.
Advantage. Deuce. A fruitful start turning into a messy end for Berdych, who slaps an easy forehand into the tape to gift Djokovic a break point.
An ace from Berdych saves the day - or does it? Djokovic challenges and the Serb, who has 20/20 vision is seems, is proved right. Still break point Djokovic... Berdych on the backfoot at the baseline... the Czech's forehand drifts wide. Djokovic bossing it.
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Tim Henman
Former British number one on BBC Two
"Berdych has a very good game, but I'd like to see him add more strings to his bow. He needs to try something different against Djokovic - what's he got to lose? It's not like he's going to come third. He's 6ft 5ins, his second serve is 88mph - and he hits it straight up the middle of the court back to Djokovic."
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Mikeh: Berdych is a bottler. Never win a slam.
John McEnerney: ND wants to do what Fed did to AM & he's all about business as usual, super clinical. He's in great form & unstoppable even 4 Fed.
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Andrew Castle
BBC tennis commentator on BBC Two
"That's Djokovic definitely through to the semi-finals. We'll be seeing him on Saturday... and most probably Sunday too."
Game and first set
Djokovic 6-2 Berdych*
The Djokovic backhand is purring, the world number one making Berdych look as if he has cement in his boots as he drills one into the corner for the first point.
A bit of fortune for Berdych, though, and the big Czech raises his racquet in acknowledgement as a mishit lob drops inside the baseline.
That is as good as it gets for the 29-year-old, though, as Djokovic accumulates two break points, needing just the one - Berdych returning long - to hold to 15.
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Andrew Castle
BBC tennis commentator on BBC Two
"Reaching the final of Wimbledon in 2010 was probably Berdych's career highlight. But he lost to Cilic in two of the Grand Slams this year. He's a consistent performer, but how do you turn him into a Grand Slam winner?"
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Sanj: #ATPFinals really should've been Djokovic v Federer every day. Guy with most wins in week gets the trophy. That would've been fun!
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Sue in Northampton: I saw Lendl win this in '85 from my hospital bed - am I right in saying his prize was a diamond studded racket?
Daniel Jellicoe: Quite simply the one thing Murray lacks is a big first serve, something Federer and Djokovic both possess. He needs to win more free points.
Please remember to put your name on your texts.
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*Djokovic 5-2 Berdych
What's happening here? Berdych wins two points on the trot to ease 30-0 ahead. The Czech in unchartered territory, never has he had such a handsome lead in this set.
Another faulty return from Djokovic, into the tramlines his forehand goes, and the Serb looks skywards and gives out a slight groan. The world number one has had little to grumble about in this set, though. It's a hold to 30 for Berdych, the Czech finding form but it's (probably) a little too late, for this set at least.
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Andrew Castle
BBC tennis commentator on BBC Two
"Three first serves in a row from 15-30 make it 5-1. You can't attack him."
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Djokovic 5-1 Berdych*
Oof! A splendid serve from Djokovic, full of spin and menace - Berdych unable to do anything other than direct it towards Boris Becker in the front row. Boris throws the ball back onto the court. I guess he doesn't need any tennis mementos.
A routine hold from the Serb, his first serve on song, as is the rest of his game to be honest.
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Stephanie Siu: Such is the allure of the BBC live feed that I'm sitting in the O2 with my bro & he's reading the feed over watching the action!
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*Djokovic 4-1 Berdych
An intake of breath from the spectators as they admiringly watch Djokovic on the run, turning defence into attack with a rasping crosscourt forehand winner.
A Berdych point! 17,000 spectators are whooping and whistling as the Czech produces an overhead at the net, eating into Djokoivc's lead. 15-30. Berdych then follows up with a snazzy ace to level at 30-30 and the Czech has some sort of momentum, pulling through to hold.
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Djokovic 4-0 Berdych*
If Djokovic reaches the semi-final with a 3-0 record in the round-robin matches, he will be guaranteed to end the year as world number one regardless of what Federer does at this tournament and the Davis Cup final. It feels as if we're heading for a routine Djokovic victory because the Serb is eye-wateringly good - feather-soft touches at the net for a hold to love.
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Robert Allen: I wonder if all these people busy writing Murray off, were the ones who said he'd never win one Grand Slam, let alone two!
Mark Farman: Andy needs to be more aggressive and punish his opponents, if his game matched his temperament he'd be number one in the world.
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Carl Keegan: Well, three games in, that just about wraps it up for Berdych.
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Andrew Castle
BBC tennis commentator on BBC Two
"Does Berdych has anything else in his game he can actually go to?"
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Tim Henman
Former British number one on BBC Two
"Another relevant tactic against Djokovic is mixing up your speed of serve. The harder you serve, the harder it comes back!"
Djokovic breaks
*Djokovic 3-0 Berdych
Berdych out of his comfort zone, dashing to the net, but his crosscourt volley drifts into the tramlines and Djokovic is ahead once again. From 15-30 to 15-40... two break points Djokovic... the crowd slow clap... Berdych shrugs his shoulders, looks towards his camp for answers...
Djokovic screws a return wide. One break point saved. Is there hope? Oh, deary me, the Czech is wide, wide, wide and Djokovic breaks once again.
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Tim Henman
Former British number one on BBC Two
"It's obviously early days in this match, but Berdych has to know that this style of play doesn't work. Are we going to see him change anything? Come to the net occasionally? On the baseline, there's only going to be one winner."
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Djokovic 2-0 Berdych*
At 30-0 Djokovic goes long and the crowd heartily applaud as Berdych wins his first point of the match. Hoorah! A double fault from Djokovic for 30-30, but for some reason it doesn't feel as if the Serb's dominance will be threatened. He launches a boomer of an ace to skip 40-30 ahead and the game ends with the familiar sight of Berdych failing to negotiate the barrier.
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James Alex: I don't think Murray will win a Grand Slam again, Nishikori and Dimitrov coming up fast now. Someone like McEnroe, Wilander, Agassi, Sampras is what Murray needs, a proven Grand Slam champion.
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Sue Barker
BBC tennis presenter on BBC Two
"We saw a masterclass from Roger Federer last night, but we could see another one from Novak Djokovic. He just seems to get better and better."
Djokovic break
*Djokovic 1-0 Berdych
The story of this match begins with Djokovic nicking the opening point before proceeding to a 0-30 lead after coming out on top of a baseline tussle. Deep breaths from the Serb, who is quickly back in position and returning brilliantly.
The net must seem like a 10ft wall for Berdych as Djokovic collects three break points and breaks thanks to a stonking backhand return. Impressive stuff from the world number one.
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Tim Henman
Former British number one on BBC Two
"With this being Berdych's last match of the year, you just want him to come out and see if he can make life uncomfortable for Djokovic."
Djokovic on top of the world
One victory - that's all Djokovic needs to ensure he end the year as the world number one. Should he achieve that feat he will join Pete Sampras, Roger Federer, Jimmy Connors, Ivan Lendl, John McEnroe and Rafael Nadal on the list of players who have finished year-end world number ones for three seasons.
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Andrew Castle
BBC tennis commentator on BBC Two
"Has Murray got the right person in his corner with Amelie Mauresmo? That's not a criticism - but I think I would be feeling a bit vulnerable if I was her. I might be getting on the phone to Ivan [Lendl] and asking 'are you sure you're not free next year?'"
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It's time to now focus on this afternoon's match because Djokovic and Berdych have strolled through the dry ice to a warm welcome and are currently warming up, while Tim Henman and Andrew Castle chat about Murray's future.
By the way, you can watch Sue and co by clicking the 'live coverage' tab on this page. There is also live coverage on BBC Radio 5 live sports extra.
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Andrew Castle
BBC tennis commentator on BBC Two
"I think what happened last night was a sporting aberration. Murray was dismissed by possibly the greatest player of all time, in full flow. Murray has played well in the last few weeks, but how's he going to compete with Nadal when he comes back, with Djokovic, and with Roger? At the age of 27, does he want to remodel his game? I think minor changes are necessary."
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What should Murray do next and where does he need to improve? Can he challenge the top three next season? You can either tweet us your thoughts using the hashtag #bbctennis, text 81111 or visit theBBC Sport Facebook page. It'll be nice to hear from you.
Special One gives Murray advice
Jose Mourinho was at the O2 last night to watch Federer gracefully progress to the semi-finals, and the Chelsea boss has some advice for Murray.
"There are some matches where we feel it's not our day and I think that applies to football and any other sport, even in tennis," said the Portuguese.
"But in all, pride, and play for the people that are behind him and even if he knows that it is very difficult to beat Roger tonight, give his best and sometimes a bad defeat is the beginning of many, many victories and hopefully next season will be a much better season for Andy."
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Tim Henman
Former British number one on BBC Two
"Federer was exceptional, but Andy was given a thumping, it's not the way he would want to finish his season."
Defeat hurts - Murray
Talking of crushing defeats... "Exceptional" is how Andy Murray described Roger Federer's performance during the world number two's 6-0 6-1 thrashing of the British number one last night.
"It was the best he's ever played against me, but I was disappointed with my performance. There's no denying how much it hurts," says Murray in his latest BBC Sport column.
"This year has been testing and I've learned a lot along the way, it's just a shame to finish it with another very harsh lesson. I'm sure it will be a tough one to look back in the future."
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Hello! Welcome to live text coverage of the last two ATP World Tour Finals round-robin matches, starting with Novak Djokovic's ding-dong with Tomas Berdych. If the rest of the week is a guide to how this afternoon's match will unfold we can expect one player (probably Djokovic) to crush the other (probably Berdych) in a straight-sets defeat, but funny things can happen at the O2.
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One person's dream is another's nightmare. A week of annihilations and humiliations is about to come to an end but, worry not, there's will be more suffering and conquering before the week is out.