Alexander Zverev beats Novak Djokovic 6-4 6-3 to win ATP Finals
German, 21, wins season-ending title for first time
'The biggest title I have ever won,' says Zverev
Zverev lost to Djokovic in straight sets in the round-robin stage
World number one Djokovic had not lost a set until the final
#bbctennis
Chew: Win or lose, Zverev is a future grand slam champion without doubt.
Alex Haworth: Novak's a little rattled. Don't think he expected Zverev to be playing this well.
Anonymous: O2 is the perfect place for the ATP finals...was at a round robin match and the atmosphere was great...don't think you could beat it
Get in touch using #bbctennis on Twitter or via text on 81111.
*Djokovic 4-6 1-1 Zverev
Djokovic eats up Zverev's serve and takes the break point at the first time of asking with a terrific return.
All level again in the second set.
Image source, Getty ImagesDjokovic 4-6 0-1 Zverev*
Double-fault from Zverev. 15-15. He's feeling the pressure now as another double-fault gives Djokovic two break points...
Image source, Reuters
Leon Smith
GB Davis Cup captain on BBC Radio (online only)
My word! I am blown away by this level, this young lad is showing the biggest heart and huge amounts of quality in all departments of his game.
The bravery to pull the trigger on that last shot after the quality of that rally was extraordinary and he's on top in every department now.
Allow Twitter content?
This article contains content provided by Twitter. We ask for your permission before anything is loaded, as they may be using cookies and other technologies. You may want to read Twitter’s cookie policy, external and privacy policy, external before accepting. To view this content choose ‘accept and continue’.
#bbctennis
Image source, Getty ImagesViv: A solid 1st set performance from Sascha. Can Novak lauch a comeback or will Sascha prevail? Tasty 2nd set coming up!
John McEnerney: I often compared Nole to the All Blacks during 2016 & now he’s back to that level but I think AZ might do an Ireland on him tonight! Changing of guard? It’s about time.
Liam Rabbitte: Strong first set. Where’s this match heading…
Get in touch using #bbctennis on Twitter or via text on 81111.
Jonathan Jurejko
BBC Sport at the O2
More and more yells of "Come on Sascha!" can be heard now. The London crowd seem to have sided with the German...
Boris Becker
Three-time Wimbledon champion on BBC TV
That's a statement shot. After a rally that was longer than 25 shots, he takes the opening game with a winner.
Djokovic 4-6 0-1 Zverev*
Zverev is playing out of his skin!
An unbelievable rally breaks out - with both players sending fizzing forehands into the corners before Zverev smashes his out of reach.
He celebrates with a fist pump and a determined glare towards his box.
Image source, Reuters*Djokovic 4-6 0-0 Zverev
Djokovic saves it with a pacey serve that Zverev can only send into the net. Djokovic then takes the advantage with a fizzing forehand into the corner.
It's back to deuce again as Djokovic makes another unforced error - sending his forehand long - and Zverev gets another break point when the Serb slices frustratingly into the net.
*Djokovic 4-6 0-0 Zverev
Djokovic moves onto 15-0 before miscuing his forehand and sending the ball up into the stands. 15-15.
He goes long on his next shot and falls behind 30-15 before Zverev's return is wide of the line. 30-30.
Another long rally goes in Zverev's favour and he has an early break point...
Image source, Getty Images*Djokovic 4-6 0-0 Zverev
Here are those stats from the first set.
Zverev hit 13 winners to Djokovic's four and the German's first-serve speed averaged 135mph, while Djokovic's averaged 115mph.
Image source, BBC Sport
Image source, BBC SportJonathan Jurejko
BBC Sport at the O2
Image source, Getty ImagesFor the first time this week Djokovic is rattled. And behind.
That's got the atmosphere cooking inside the O2. Ladies and gentlemen, we finally have a match...
Djokovic 4-6 Zverev
Seven aces and 88% points won on his first serve - what a set from Alexander Zverev! He only needed one break point and he has taken 56% of the total points on offer.
Djokovic 4-6 Zverev
Zverev comes into the net but Djokovic's passing shot has too much pace on it and the German flops it into the cords.
Djokovic then sends his forehand long and Zverev takes the lead in this final.
Image source, Getty ImagesDjokovic 4-5 Zverev*
Can he settle the nerves?
Yes he can. An ace brings up 15-0 for Zverev. And another smashing serve is planted into the net by Djokovic. 30-0.
Another ace. 40-0. Set point...
Djokovic 4-5 Zverev*
Boris Becker
Three-time Wimbledon champion on BBC TV
It needed a young player to finally step up to the plate and challenge the big boys. Zverev's got a big chance to win the first set but it's important for all of us to see the future of tennis and see that there's a life after.
Image source, Getty ImagesLeon Smith
GB Davis Cup captain on BBC Radio
This is a high-quality match with service winners, groundstroke winners, net winners and a number of long exchanges. There haven't been many poor shots.
Djokovic 4-5 Zverev*
The pressure takes its toll as a return is flashed back at him by Zverev and Djokovic slumps a forehand into the net.
That's the first time he has been broken in this tournament this year. And what a time to do it. Zverev will serve for the first set.
*Djokovic 4-4 Zverev
Djokovic dictates the play perfectly in the rally before fluffing up the volley at the net. 15-15. He then pushes his backhand passing shot wide and Zverev moves 30-15 ahead.
The Serb sends a huge forehand into the corner which Zverev can only slice into the net but the German brings up break point when Djokovic sends it long.