US 15-year-old Coco Gauff advanced to a third-round US Open showdown with top-seeded defending champion Naomi Osaka on Thursday by defeating Hungarian qualifier Timea Babos 6-2, 4-6, 6-4.
Gauff, who made a sensational run to the fourth round at Wimbledon before falling to eventual champion Simona Halep, became the youngest player in the last 32 at a US Open since Russian Anna Kournikova made the last 16 in 1996.
Nadal advances by walkover
Three-times champion Rafael Nadal got a walkover into the third round of the US Open after Australian wildcard Thanasi Kokkinakis withdrew from their match with a right shoulder injury.
Nadal will now face South Korean Chung Hyeon in the third round.
Halep loses to US qualifier Townsend
Romanian fourth seed Simona Halep crashed out in the second round after losing 2-6, 6-3, 7-6(4) to Taylor Townsend.
The 23-year-old American struck 39 winners to Halep's 23, won 17 points at the net and held her nerve in a thrilling third set tiebreak to advance despite making 42 unforced errors.
Czech sixth seed Kvitova ousted
Petra Kvitova became the first top 10 seed in the women's draw to be knocked out as Germany's Andrea Petkovic toppled the sixth seed 6-4, 6-4.
Although Kvitova had 23 winners, nearly twice the number of her opponent, it was Petkovic who converted three of six break points to move into the third round.
Kyrgios advances with ease
Nick Kyrgios kept a lid on his temper and served up a masterclass to beat France's Antoine Hoang 6-4 6-2 6-4.
The fiery Australian 28th seed sent down 24 aces, including one on his second serve, and cracked 40 winners to reach the third round, where he will face unseeded Russian Andrey Rublev.
Zverev wins his second five-setter
Sixth seed Alexander Zverev won his second consecutive five-setter of the tournament, beating American Frances Tiafoe 6-3, 3-6, 6-2, 2-6, 3-6.
German Zverev struggled to land his first serve at times, but still fired 22 aces and 63 winners and will face either Aljaz Bedene or Benoit Paire in the third round.
Petkovic's belly and besties
Germany's Andrea Petkovic showed her abdomen in a post-win celebration to make good a threat to mock her trainer if he kept staring at his abs in a mirror, then called out friends who cheered her to victory.
"The strange people in the corner, those are my friends. It makes it so special I could win in front of them," she said. Asked about them later, Petkovic said, "I think they are already at the bar. I'm not sure I want to see them right now."
Sweet Caroline loves New York
Just as you can count on the song "Sweet Caroline" to be played when Danish 19th seed Caroline Wozniacki is playing at the US Open, you can tell she has a true affinity for New York, keeping an apartment year-round in the Big Apple.
"I really enjoy the city," she said, listing her favorite neighborhoods as the Flatiron District — "It's cool, there's a lot of good restaurants and stuff" — the Upper Eastside and "if you want to check out some nice little restaurants and bars as well, I think the West Village is cool."
Caroline Wozniacki rallied from a set down to beat American Danielle Collins 4-6, 6-3, 6-4.