American teenage sensation Coco Gauff continued another superb run at a grand slam event with a hard-fought 6-2 4-6 6-4 victory over Hungarian qualifier Timea Babos to set up a third-round showdown with world no 1 and defending champion Naomi Osaka at the US Open.
The 15-year-old wildcard Gauff overcame world no 112 Babos after two hours and 21 minutes of play, becoming the youngest woman to reach the last 32 at Flushing Meadows since Anna Kournikova's run in 1996.
Gauff, ranked at a career-high world no 140, extended her success in Grand Slam play, following up on her sensational fourth-round showing at Wimbledon.
"It was great," Gauff said after the match. "I thought the first set, I definitely was in control. In the second set, [Babos] raised her level and I wasn't able to finish the set. But she played amazing. I thought I played well, too. It was a great match.
"Being American, playing in New York is amazing. I knew obviously I was going to be the favourite, especially after Wimbledon, but also being American. (But) I didn't think it was going to be like that."
Gauff said she "did feel less nervous" than she in her US Open main-draw debut in the first round, adding: "When you first walk out on Armstrong in general, it's a nervous feeling.
"So I'm glad that I was able to get through that first round. Today I was prepared and knew what to expect. I think that helped me in today's match."
Caroline Wozniacki advanced to the third round, fighting back a challenge from American Danielle Collins to win 4-6 6-3 6-4.
Nick Kyrgios had a relatively easy victory against Antoine Hoang 6-4 6-2 6-4 to reach the third round, while second-seeded Rafael Nadal advanced with a walkover after second-round opponent Thanasi Kokkinakis pulled out before their match with a right shoulder injury.