Novak Djokovic fended off a fading Andy Murray 7-6 (1), 6-7 (1), 6-2, 6-4 in a matchup of past US Open champions to reach the tournament's semifinals for the eighth consecutive year.
It took a while for the No. 1-ranked and No. 1-seeded Djokovic to push himself out front in a well-played, back-and-forth, 3-hour, 32-minute match that ended after 1 am on Thursday.
Djokovic broke the eighth-seeded Murray to go up 3-1 in the third set, then fended off a pair of break points in the next game. On the first, Murray sailed a backhand long to end a 28-stroke point, then leaned over and put a hand on his knee. On the second, he dumped a forehand into the net, then slammed his racket against his right thigh and yelled.
On Saturday, Djokovic will take on 10th-seeded Kei Nishikori, the first man from Japan to reach the US Open semifinals since Ichiya Kumagae in 1918. Nishikori outlasted third-seeded Stan Wawrinka of Switzerland 3-6, 7-5, 7-6 (7), 6-7 (5), 6-4 earlier Wednesday.
That match lasted more than four hours, and Nishikori managed to shake off any lingering exhaustion from his previous victory, which took 4:19 and ended at 2:26 am Tuesday, equalling the latest finish in tournament history.
For two sets, Djokovic-Murray was reminiscent -- in terms of pure entertainment value and setting, if not quite star power -- of the 2001 classic between Pete Sampras and Andre Agassi, which also was a quarterfinal, and also under the lights at Arthur Ashe Stadium. That one, won by Sampras, featured four tiebreakers, because neither man broke serve even once.
If the sublime-serving Sampras against the terrific-returning Agassi provided a contrast in styles, Djokovic versus Murray was more a case of mirror images. Two of today's top returners, they combined for 11 service breaks, seven by Djokovic, including in the final game. They are also both brilliant baseliners and retrievers, and it helps that they know each other -- and each other's patterns -- so well.