us open 2014: Novak Djokovic defeated by Kei Nishikori.

The tenth seed from Japan produced a quite superb display to record a 6-4 1-6 7-6 (7/4) 6-3 triumph, becoming the first Asian man to reach the final of a grand slam tournament.

Despite having to come through gruelling five-setters in both previous rounds, Nishikori displayed tremendous endurance on a scorching day in New York as both players battled the heat as well as each other.

Djokovic - who was bidding to reach a fifth consecutive final at the event - looked to have asserted himself on the match as he raced through the second set after dropping the first, but the nine-time grand slam champion was ultimately undone by the ferocity and consistency of Nishikori's groundstrokes as the 24-year-old clinched a career victory.

"I don't know what's going on," a delighted Nishikori stated immediately after his win. "I was a little bit tight, especially with my first semi-final in a grand slam. It's just an amazing feeling, beating the number one player and playing much better than the last couple of matches.

"I'm so happy. It was tough conditions but I guess I love to play long matches and I hope I can recover well for the final.

If Nishikori was tired or nervous going into his first semi-final, he did not show it, more than matching Djokovic from the back of the court.

An early break came and went but Nishikori was the one dictating a lot of the points and he placed a forehand return onto the outside of the line to move ahead again at 4-3, this time making the advantage count as he served out for the set.