Kei Nishikori fell in five sets to Benoit Paire of France in the first round of the U.S. Open on Monday.
"It's disappointing, but it's more my opponent playing well than my playing badly," said the fourth-seeded Nishikori, a finalist in last year's event, after his 6-4, 3-6, 4-6, 7-6 (8-6), 6-4 defeat.
"It's disappointing since it's the first time in years I've lost in the first round at a big tournament."