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Novak Djokovic needs to ask himself: what would Bruce Willis do when in a pickle? Bruce would probably launch an ace at his nemesis, which the Serb does, and then send one thudding forehand after another towards his opponent's direction until his rival crumbles, which the Serb does. A straightforward hold.

Piers Newbery
BBC Sport at Flushing Meadows

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"Few people outside the Nishikori camp can have predicted the first set going that way, with the Japanese player dominating behind his forehand, described by John McEnroe as 'one of the great shots in our sport'.

"The Djokovic second serve would not qualify for that description at the moment as it's getting taken to pieces, with the Serb winning just three points behind it in the first set."

Pat Cash
1987 Wimbledon champion on BBC Radio 5 live

"Nishikori is the one who has settled down the best. He has played some good tennis and tactically it is almost as if Djokovic has expected Nishikori to fall. Djokovic is not going out there to win at the moment, he is going out not to lose it. Nishikori has been punishing those short balls."

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A hush descends on the usually boisterous Ashe as Nishikori steps up to start this game. It was so quiet you could hear a spectator blink. Djokovic, eyes widening, getting ready for a punch-up, but he's unable to get his opponent into a headlock.

A casual Djokovic backhand drifts long. Nishikori with a nerve-easing unreturnable serve down the 'T'. 40-15 and the crowd applaud the under dog. Nishikori, playing in his first Grand Slam semi-final, but concluding the first set like an old pro.

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Ole! Today is a good day to be Kei Nishikori. A two-handed backhand threaded down the line has the spectators purring as Nishikori advances to 15-30. But he slaps into the net on the next point and Djokovic reduces the arrears - an ace followed by a confident serve and volley. Nishikori to serve for the set.

Pat Cash
1987 Wimbledon champion on BBC Radio 5 live

"Kei Nishikori is doing the right things at the minute. He is very relaxed. Djokovic is the one who looks very tense. He knows he has a fight on his hands.

"When Nishikori is in trouble he is just absolutely unleashing, he knows he doesn't want to get dragged from side to side by Djokovic. So far his big shots are going in."

Djokovic isn't the sort of man to be easily rolled over. When you think he's dead, he usually comes bouncing back. But a 118mph boomer of a first serve down the 'T' - Nishikori's fastest of the day has the beating of Djokovic and there will be no Djokovic fight back in this game. A trouble free hold to 15 for the 10th seed.

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Nishikori has ripped up the script and decided to write his own story, a romantic tale of an underdog, a man who has already come through two epic five-setters, rattling the best player on the planet.

A wonderful backhand down the line earns Nishikori three break points. A change of tactic from Djokovic as he volleys his way out of danger. One break point saved. Exquisite shot-making from Nishikori, a down-the-line forehand clips the line and Djokovic is broken once again.

It seems to be hotter than a volcano's belly on Ashe. Neither player troubled by the temperature as they go lunging from tramline to tramline in a lengthy game.

At 15-15, Nishikori nets a straightforward backhand volley, another unforced error from the 10th seed's racquet. Admirable athleticism from Djokovic on the baseline...he seems to be playing his opponent as if he were a computer game, but the Serb comes a cropper when in a position of dominance - ballooning a forehand long. He despairingly raises his arms and blames a spectator's yell. Opportunity missed. Nishikori marches on.

Russell Fuller
BBC tennis correspondent at Flushing Meadows

"Many people were concerned about Djokovic with his form below his usual high standards coming into the tournament, yet he has Grand Slam pedigree."

Djokovic back to his best on the next game, serving with aplomb. Nishikori netting a return on the final point and the game seems to be over before it truly began. Hold to 15.

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Andy Murray broke Djokovic in the opening game of their quarter-final, but Djokovic responded by immediately breaking back. The Serb nicks two early points off the Nishikori serve, then drags his opponent into a lengthy baseline exchange and Nishikori butchers a backhand. Three break points Djokovic. He needs just the one. Nishikori goes long and it's as we were.

Pat Cash
1987 Wimbledon champion on BBC Radio 5 live

"A poor game from Djokovic. Kei Nishikori's coach Michael Chang had a very similar style of play. With his experience he would have said to Nishikori 'in my career I wished I had bit more oomph in my game to compete with the Agassis and Sampras' - you are going to have to step it up and have more power'. That's exactly what he did then to get the break. Djokovic got the first shot back, but he couldn't do anything about the next one. Nishikori has speed and some real weapons."

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Kei Nishikori's mum, Eri, is on the sidelines watching her son in his first Grand Slam semi-final, which is nice, and she has much to be proud of in this game.

The 10th seed's backhand clips the net, but the pouncing Djokovic is unable to take advantage, slapping his volley into the tramlines. A nasty-looking slip from Djokovic on the baseline as he watches Nishikori's return bounce long. All square at 30-30. Careless from Djokovic as he goes long - break point Nishikori! And it's a brilliant point from the 24-year-old as he works Djokovic out wide and kills him off with a thumping forehand down the other side. Cripes.

John McEnerney:, external "Novak to dispatch Kei fairly quickly. This is the Big Boys' Playground & the big boys will do their thing. Wimbledon final repeat."

Piers Newbery
BBC Sport at Flushing Meadows

"Nishikori has spent 13 hours and 34 minutes on court battling through to the last four, but asked just now how he is feeling, he replied: 'Not too bad. I had two days, so I recovered well. It wasn't easy but now it's good. It's always tough to play Novak, he's very steady and won't give me free points, so I'll have to stay concentrated'."

Who was the first Japanese player to reach the semi-finals of a Grand Slam? I can help with that question. It was Ichiya Kumagae, who made the last four of the US Championships in 1918 when the tournament was held in Forest Hills.

Back to the tennis, an energy-sapping rally for the first point, with Nishikori coming out on top. The underdog screws a backhand down the line on the next point. 15-15. Djokovic nets a return, but the 10th seeds gives the world number one a sniff with a faulty forehand. 30-30.

A confident one-two from Nishikori, though - a first serve out wide followed by a winning return to the other side. But, again, he gives the game's finest retriever hope so to deuce we go. Advantage. Deuce. A mammoth first service game is not what the player from Japan needs... Testing times for Nishikori, but he pulls through.

Pat Cash
1987 Wimbledon champion on BBC Radio 5 live

"What a terrific week for Kei Nishikori. He's had a couple of really tough five-set matches. He's been the tougher player, the better player and he has shown progress the last couple of years. He's quick, his backhand is world class, his serve is something that needed to be worked on and he has.

"It is now very solid. Now he is a real threat, he scares these players. We saw how well he played versus Nadal in Madrid before he got hurt and last time he played Djokovic he won the third set 6-0!"

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Djokovic gets the match under way and does so with an iffy first serve which is way out of bounds. "OUT" screams the linesman, though he really needn't have bothered. Djokovic rattles off three easy points, the 10th seed going long and then netting a return, and the Serb finishes with an ace down the 'T' for a comfortable hold to love.