Kei Nishikori had a couple of nervy moments early, but managed to get on track to win his match against Frenchman Nicolas Mahut in four sets during the third round of the U.S. Open at Flushing Meadows on Saturday.

Playing into the New York evening, Nishikori overcame a slow start after dropping the first set, going on to claim the final three and the match with little further trouble (4-6, 6-1, 6-2, 6-2).

"Today I was pretty aggressive and played some good tennis." said Nishikori who reached the tournament's fourth round for the third time.