MELBOURNE, Australia — Fifth-seeded Kevin Anderson let a sizable lead slip away amid problems with his serving arm and lost to the 20-year-old American Frances Tiafoe, 4-6, 6-4, 6-4, 7-5, in the Australian Open’s second round on Wednesday.
Anderson was the runner-up at Wimbledon last year and the U.S. Open in 2017, and he had won all three of his previous matchups against the 39th-ranked Tiafoe.
But after trailing by a set and 3-0 in the second, Tiafoe turned the match around to get to the third round at a major tournament for the second time.
Anderson received several visits from a trainer for his bothersome right arm.
Sloane Stephens opened the day on Rod Laver Arena by advancing at the expense of her former doubles partner Timea Babos in a second-round match the women’s tour billed as a battle of the so-called frenemies.
Fifth-seeded Stephens, the 2017 United States Open champion, looked strong in a 6-3, 6-1 victory, but Babos kept her working by saving 18 of the 23 break points she faced.
The players combined to win three junior Grand Slam doubles titles — the French, Wimbledon and United States Open — in 2010.
Stephens said she knew what to expect from Babos but that did not make it any smoother.
“I just had to hang in there and be patient,” she said.
Stephens will next play No. 31-seeded Petra Martic, who beat Marketa Vondrousova, 6-4, 7-5.
This is the first time since 2014 that Stephens has put back-to-back wins together at Melbourne Park. She reached the fourth round in 2014, a year after making a run to the semifinals.
“It’s tough getting back into the swing of things,” Stephens said of her preparation for the season-opening major, which this month included first- and second-round losses in Brisbane and Sydney. “It’s a little bit toasty, but a beautiful place to play.”
In other early women’s matches Wednesday, Anastasia Pavlyuchenkova eliminated ninth-seeded Kiki Bertens, 3-6, 6-3, 6-3, to reach the third round of a major for the first time since her quarterfinal run here in 2017, and Aliaksandra Sasnovich beat 20th-seeded Anett Kontaveit, 6-3, 6-3.
No. 19-seeded Caroline Garcia advanced with a 6-3, 6-3 victory against Zoe Hives.
Stefanos Tsitsipas is also through to the next round and closer to a potential meeting with the defending champion Roger Federer, who beat the qualifier Daniel Evans, 7-6 (5), 7-6 (3), 6-3.
Tsitsipas defeated Viktor Troicki, 6-3, 2-6, 6-2, 7-5, but wasted a lot of break-point opportunities as Troicki saved 15 of 19 chances created by Tsitsipas.
Considered one of the new breed of young talented players on the ATP Tour, the 20-year-old Tsitsipas won at Stockholm last year and was a finalist in two other tournaments.
He will next play 19th-seeded Nikoloz Basilashvili, who beat Stefano Travaglie, 6-3, 3-6, 6-3, 4-6, 6-3, also on Wednesday.