American Madison Keys and No. 2 Aryna Sabalenka breezed into the US Open third round on Wednesday, while reigning Wimbledon champion Barbora Krejcikova became the third women's top-10 seed to fall.
No. 14 seed Keys, a US Open finalist in 2017 and crowd favorite, sprinted past incoming Texas freshman Maya Joint 6-4, 6-0 in 62 minutes. She next faces No. 33 Elise Mertens of Belgium.
"After the first set I feel like I made a few adjustments on my returns just to put a little bit more pressure on her," said Keys, who retired from her two previous tournaments at Wimbledon and Toronto. "And I felt like once I was able to get a little bit out ahead I really just ran with the moment and was able to close it out really well."
Keys, who made her major main draw debut at the 2011 US Open, has 60 wins at hard-court Slams, third most among women in that span after only Serena Williams and Victoria Azarenka.
Sabalenka, one of the favorites to win the tournament, faced little resistance from Lucia Bronzetti in a routine 6-3, 6-1 win. She put her punishing serve to good use, pounding five aces to just one double fault, and did not face a break point.
Sabalenka, last year's US Open runner-up, improved to 13-1 in major matches this year and has now won 27 of the 29 sets she's played this season in slams. The only sets she's lost came in her French Open quarterfinal loss to Mirra Andreeva.
Next up for Sabalenka is a third-round meeting with 29th seed Ekaterina Alexandrova, who needed three sets to get past 16-year-old American Iva Jovic 4-6, 6-4, 7-5.
The No. 8-seeded Krejcikova lost to qualifier Elena-Gabriela Ruse (world No. 122) 6-4, 7-5, joining No. 9 Maria Sakkari and No. 10 Jelena Ostapenko in making an early exit from Flushing Meadows.
Krejcikova won her second Grand Slam singles title this summer, but she didn't play any matches after the Paris Olympics. She acknowledged last week not knowing where her level of play was.
Turns out, it wasn't good enough.
"I mean, winning Wimbledon is amazing. It's a great, great, great result, I'm very proud about it and how I was able to handle everything there," said Krejcikova, who hadn't played a tournament on hard courts since February.
"I think I was playing quite well, definitely better than in the first match. I think my game was improving, but it just wasn't enough."
Ruse got much more work on the US Open's hard courts while playing her way into the main draw through the qualifying tournament and was better than Krejcikova on the points that mattered most, fighting back from a 5-3 deficit in the second set to win the final four games.
"Barbora, she's such a good player, she's won so many matches in the last two years and it's just a dream for me," said Ruse, 26, who's from Romania.
No woman has won Wimbledon and the US Open in the same year since Serena Williams in 2012.
Ruse advanced to the third round of a Grand Slam for the first time and will play No. 26 seed Paula Badosa, who eliminated American Taylor Townsend 6-3, 7-5.
Badosa continued her resurgence in a strong summer by reaching the third round of the US Open for the first time.
"I know it's just a third round, but I was really looking forward to doing this in New York," said Badosa, a Spaniard who was born in New York.
Mertens knocked out Australia's Ajla Tomljanovic 6-3, 6-2. Mertens has reached the third round or better in 23 of her 27 major appearances since the start of 2018, the most third-round appearances at majors of any woman in that span.
American Emma Navarro swept past Arantxa Rus 6-1, 6-1. The 13th seed reached the third round for the first time and will play Ukraine's Marta Kostyuk next.
Olympic champion Zheng Qinwen of China survived an early scare to overcome Andreeva 6-7 (3), 6-1, 6-2.
Despite Andreeva taking an early lead and then clinching the tiebreak, Zheng clawed her way back into the match behind a solid first serve as she finished with 36 winners and 20 aces.
The No. 7-seeded Zheng is the third women's top-10 seed in the Open era to win each of her first two matches of a US Open from a set down. The others are Mary Joe Fernandez (1992) and Dinara Safina (2009).
With temperatures surpassing 90 degrees Fahrenheit, the extreme weather policy was in effect Wednesday at the Billie Jean King National Tennis Center, meaning players are allowed a 10-minute break before the second and third sets.
"I just wanted to get on and get off," said Keys.
Zheng placed an ice towel around her head under the blazing sun on Grandstand.
"Today the weather is too hot. Yeah, but all the crowd is here suffering with me from the heat," said Zheng, who next plays Germany's Jule Niemeier, a 6-4, 6-0 winner over Moyuka Uchijima of Japan.
ESPN Stats & Information, The Associated Press and Reuters contributed to this report.