Federer looks to be playing a lot more relaxed at this moment. He is executing his shots to perfection as he goes 15-30 ahead. Cilic falls back on his trusted weapon, his serves to wrap the game. Federer 3 Cilic 3
Great serves from Federer as he wraps up the game quickly dropping just a single point. Federer 3 Cilic 2
Another stiff contest before Cilic manages to hold his serve. The Croatian is trying to drain Federer out with those long rallies. Federer 2 Cilic 2
BREAK! Cilic responds back immediately to snatch a double breakpoint. Federer manages to save the first one but Cilic wins the next to win the break back. Federer 2 Cilic 1
BREAK! It looks like Federer plays at a different level after the second set. He did that against Monfils and he is 0-30 leading Cilic's serve and then earning a breakpoint. A lovely backhand winner gives him the first break of the match. Federer 2 Cilic 0
Federer gets his focus back as he makes a dominating start to the third set holding his serve without losing a point. Federer 1 Cilic 0
SECOND SET: MARIN CILIC 6 ROGER FEDERER 4
It's another simple game for Cilic as he continues to dominate the proceedings. He loses just one point as he wraps the the second set. Federer 4 Cilic 5
Federer goes quickly to 40-15 before unforced errors from the Swiss ensures its deuce. Cilic has a breakpoint but good serves ensures Federer keeps his serve. Cilic serves for the set. Federer 4 Cilic 5
Federer begins well to take a 0-15 lead but Cilic serves well to win the next three points. Federer gets another but Cilic finishes it off with Federer finding the net. Federer 3 Cilic 5
Another good game for Federer but not before a stunning lob shot from Cilic to make it 40-30. An ace from the Swiss follows and he holds serve. Federer 3 Cilic 4
Cilic at his best as he takes four straight points to including an impressive winner to keep the serve. Federer 2 Cilic 4
Cilic is not letting Federer settle earning 15-30 lead but the Swiss still manages to keep it going with some impressive forehand shots. Federer 2 Cilic 3
Federer looks to be getting into the groove as he gets to 30-all but two backhand shots go horribly wrong as Cilic continues to hold his serve. Federer 1 Cilic 3
A good game for Federer. Gets his serves and shots in the right areas. He needs to keep the good work going. Federer 1 Cilic 2
Great serves again from Cilic as he races to 40-0 before Federer manages to pull back it to 40-30. Cilic gets his composure back to win the crucial point as he holds serve. The Swiss challenges the point but is not lucky. Federer 0 Cilic 2
BREAK! Cilic starts of the second set in style earning himself a triple breakpoint. Federer manages to save two of them before surrendering the last one. That's a quick break for the Croatian. Federer 0 Cilic 1
FIRST SET: MARIN CILIC 6 ROGER FEDERER 3
Cilic keeps the momentum going as he holds serve. He was in a comfortable position with three set points of which he wins the first. Cilic 6 Federer 3
Great serves from Federer including a couple of aces as he holds his serve without much fuss. Cilic serves for the set. Cilic 5 Federer 3
Cilic keeps it simple as he is just one game away from the first set. His serves have been spot on. Cilic 5 Federer 2
Federer keeps his serve but he is a break down and he will be keen to win it immediately. Cilic 4 Federer 2
Cilic is pushing Federer to the limits playing his baseline shots to perfection. But Federer is not letting it slip away as he surges to a 15-30 lead and then earns a breakpoint at 30-40. Cilic saves it to take it to deuce before fine serves ensures the Croatian holds serve. Cilic 4 Federer 1
BREAK! Federer races to 40-0 with some brilliant serves but Cilic fights back to force the game into deuce and then also take the advantage. He is returning the serves well as he earns the first break. Cilic 3 Federer 1
Brilliant serves from Cilic as he doesn't loses a point to take his serve. Cilic 2 Federer 1
Federer serves couple of aces as he comfortably seal his serve. Cilic 1 Federer 1
Cilic big serving is there to see in the start of the match. But Federer is equally dominating with some powerful forehand shots. But, Cilic is undettered as he opens his account. Cilic 1 Federer 0
FIRST SEMIFINALS REPORT
In a remarkable display of endurance, Nishikori followed up punishing five-set wins over third seed Stan Wawrinka and fifth seed Milos Raonic with an even more extraordinary effort, grinding down the top-ranked Djokovic in two hours, 52 minutes on a sweltering Arthur Ashe Stadium court.
"It's just amazing, an amazing feeling beating the number one player and also playing much better in these couple of matches so I'm so happy," the 10th-seeded Nishikori said.
"It was really tough conditions today, felt a little bit heavy and humid too but I guess I love to play long matches and I hope I can recover well for the final."
Nishikori denied Djokovic a fifth successive trip to the U.S. Open final.
The 24-year-old Japanese awaits the winner of the second semi-final between world number two and five-times U.S. Open champion Roger Federer and 14th seed Marin Cilic in Monday's final.
"I don't know what's going on," said Nishikori, who is coached by former grand slam champion Michael Chang. "I was a little bit tight; especially it was my first semi-final in a grand slam."
Djokovic was magnanimous in defeat.
"It was not easy to play in these conditions but also he had more hours spent on the court. So it's no excuse," the Serb said.
"I expected him to be able to play another five-setter because he had two days off.
"He just played better in these conditions than I did.
"I just wasn't managing to go through the ball in the court. You know, I wasn't in the balance. Unforced errors. Even when the ball gets back to his part of the court it's pretty short; he takes advantage of it. On the other side I didn't. That's it."
Nishikori arrived at sun-bathed Arthur Ashe Stadium looking fresh despite having played the latest finishing match ever at the U.S. Open on Tuesday in the fourth round against Raonic, when he walked off court at 2:26 a.m. local time.
Two days later Nishikori was forced to go the distance again, out-lasting Wawrinka in a four hour, 15 minute battle.
But the biggest test of all came with gusting wind, stifling humidity and courtside temperatures hovering around 100 degrees (Fahrenheit), turning the semi-final into a survival of the fittest against a surging world number one who had dropped just one set on route to the final four.
Nishikori, appearing in his first grand slam semi-final, got the match off to a bright start by breaking Djokovic to go up 4-3 on the way to taking the opening set.
But the Wimbledon champion upped his game in the second, dominating play with a pair of breaks before finishing off the set with a thundering ace.
The battle intensified in the third as the two men, sweat pouring off them, exchanged breaks to send the set to a tiebreak.
Nishikori took the initiative, racing to a 4-0 lead before Djokovic staged a rally but could not wrestle the advantage away from the Japanese dynamo who went on to claim the breaker 7-4.
The tiebreak appeared to give Nishikori a huge boost, the 10th seed returning to court and immediately breaking the Serb to take control of the set.
"He (Djokovic) started to play much better, very consistent and being more aggressive," said Nishikori. "I tried to forget about the first and second set and tried to concentrate again.
"I hope it's big news in Japan. I feel the support from Japan even from the TV even though it's 4 o'clock in the morning but I hope a lot of people watching."
PREVIEW
Roger Federer will take on Marin Cilic in the second semifinals of the US Open.
The Swiss pulled off a thrilling win after being down two sets.