Rafael Nadal, defending US Open Champion and World No. 1, retired from the semi-final clash against Argentina's Juan Martin del Potro in the men's singles on Friday in the US Open owing to a nagging knee injury.
Nadal's marathon, five-set thriller in extreme heat and humid conditions on Wednesday against Austria's Dominic Thiem seems to have made him unfit for Friday's match as he gave up on the five set thriller.
Nadal's withdrawal cleared the way for del Potro to enter the final where he is set to meet Serbian legend and World No. 6 Novak Djokovic who eased past Japan's Kei Nishikori after registering a 6-3, 6-4, 6-2 scoreline. If he wins the final it will be Djokovic's third US Open title and his second Grand Slam of the year after the Wimbledon win earlier this year
The game started on an ominous note for Nadal as del Potro broke his serve in the first game of the first set. However, Nadal returned the favour in the following game and levelled the score at 1-1. After holding their serves for three games each, del Potro broke Nadal's serve to inch ahead at 5-4, with Nadal levelling the score again in the next game.
The first set advanced to the tiebreaker after Argentina's World No. 3 drew back at 6-6. An array of unforced errors for the Spaniard resulted in the first set going del Potro's way.
The two have faced off in the US Open semi-finals twice before, with del Potro beating the Spaniard in 2009 on route to his first Grand slam win. Nadal bested the Argentine in their meeting last year.
The second set was where Nadal's knee problems started aggravating, with a trainer coming on to the court to re-tape Nadal's right knee after it ripped off. His knee was also taped in the first set.
Nadal's injury restricted his movement to a great extent and caused him to eventually concede the set 2-6, with the five-time US Open champion walking up to the chair umpire and confirming his retirement from the match.
Meanwhile, Djokovic was never in threat of an upset by the current World No. 21, Nishikori, as he raced to a 3-0 lead in the first set. Although Nishikori managed to claw back three games to make it 5-3, Djokovic held him to love and sealed the first set with an ace.
A better start for Nishikori in the second set saw him level with the holder of 13 Grand Slam Titles at 2-2. Djokovic broke Nishikori's next serve and, with Nishikori unable to break any of the Serbian's serves, the second set went to Djokovic's name at 6-4.
Djokovic went into cruise control in the third set, winning four consecutive games from 2-2 to win the match and book his spot in the final.