NEW YORK - Iga Swiatek survived a surprise U.S. Open second-round test on Thursday as men's top seed Jannik Sinner and Japan's four-times major winner Naomi Osaka cruised through.

Second seed Swiatek, who arrived in New York after collecting her sixth major at Wimbledon and winning the Cincinnati tune-up tournament, had to battle hard to beat unseeded Suzan Lamens 6-1 4-6 6-4 on Arthur Ashe Stadium.

"It got a bit complicated in the second set, but I'm happy that I could reset and start playing better in the third set," said the 2022 tournament winner who closed out the match with an ace to set up a meeting with 29th seed Anna Kalinskaya.

Defending champion Sinner, the world number one, crushed Australian Alexei Popyrin in a ruthless performance 6-3 6-2 6-2 to book a third-round match with Canadian 27th seed Denis Shapovalov.

Osaka, seeded 23rd, beat American Hailey Baptiste 6-3 6-1 in the first match at Louis Armstrong Stadium, reaching the third round of the tournament she has won twice for the first time since 2021.

"I was just really trying to focus and not give her any free points and just be positive," Osaka said. "I'm really excited to be moving better."

It was the second of two lop-sided matches on Armstrong, after Italy's 10th-ranked Lorenzo Musetti saved nine of the 11 break points he faced to beat unseeded Belgian David Goffin 6-4 6-0 6-2.

VENUS MOVED

Two early finishes allowed organisers to move a highly-anticipated first-round doubles match involving 45-year-old Venus Williams to the second-largest stadium, where fans packed the house.

Seven-times major winner Williams, who lost in the mixed doubles and women's singles first rounds, found inspiration from Canadian partner Leylah Fernandez as they beat sixth seeds Lyudmyla Kichenok and Ellen Perez 7-6(4) 6-3.

"This is the best partner I've ever played with outside Serena," said Williams, who this summer became the oldest player to win a WTA singles match since 2004. "We're a great team."

Coco Gauff, the 2023 champion, will again be in the spotlight when she kicks off the night session at Arthur Ashe Stadium against Croatian Donna Vekic, who knocked her out of last year's Paris Games en route to the Olympic silver medal.

The American third seed will hope for an easier time after needing nearly three hours to get past Ajla Tomljanovic in the opening round.

Gauff's compatriot Tommy Paul, the men's 14th seed, plays Portugal's Nuno Borges in the final match on Ashe.

German third seed Alexander Zverev continues his bid for a maiden major title against Briton Jacob Fearnley in the late session at Louis Armstrong Stadium. REUTERS