Novak Djokovic saw off Britain's Andy Murray in a tense late-night contest to reach the US Open semi-finals.
The world number one came through 7-6 (7-1) 6-7 (1-7) 6-2 6-4 in a match that lasted three hours and 32 minutes.
Djokovic will now play Japanese 10th seed Kei Nishikori in the last four on Friday.
More from the match:
Murray peaked in the second set but appeared to tire in the third and fourth
Murray feels the pain in the fourth set
Under the guidance of coach Boris Becker, Djokovic won 71% of net points
Murray hit more winners - 47 to 46 - but also more unforced errors 65 to 48
Djokovic: "We both gave our best and at times the tennis was not nice"