Maria Sakkari, the sixth-seeded Greek player, defeated Russian teenager Diana Shnaider in the second round of the Australian Open after coming from behind.
While playing in the American college system, Shnaider, 18, has yet to make the transition to the professional ranks but threatened an upset by winning the opening set.
To win 3-6 7-5 6-3 and earn her third match point, Sakkari rallied.
Iga Swiatek of Poland, the top seed, and Jessica Pegula of the United States, the third seed, both won in straight sets.
Swiatek defeated Camila Osario of Colombia 6-2, 6-3, while Pegula defeated Aliaksandra Sasnovich of Belarus 6-2, 7-6 (7-5).
In support of NFL player Damar Hamlin, who was released from the hospital nine days after having a heart arrest while playing for the Buffalo Bills, the team owned by her parents, Pegula played with the number three on her skirt.
Pegula declared, “It’s amazing and awesome to see that he has healed.”
Daria Kasatkina of Russia, the eighth seed, was beaten 6-1, 6-1 by compatriot Varvara Gracheva at this year’s tournament, becoming the first top-10 player to lose in the women’s draw.
“Perhaps she ought to think about forgoing college.”
Shnaider, a freshman at North Carolina State University in the United States, proved in Melbourne that she can play with the best. She is a left-hander with a fierce forehand.
She advanced through three rounds of qualifying to make her Grand Slam main-draw debut, winning in straight sets while challenging Sakkari throughout their two-and-a-half-hour match.
The two-time Grand Slam semifinalist Sakkari said, “She is very young and very promising; maybe she might consider forgoing college and turning pro.”
“I was hesitant because it’s challenging to play someone you’ve never played before. She was playing forcefully and swung hard. I made an effort to find solutions because I believe I am good at it.
It was pretty impressive work from both of us.
The 2019 finalist and 15th seed Petra Kvitova earlier lost to Ukrainian Anhelina Kalinina 7-5, 6-4, becoming the first top-20 seed to lose.
Coco Gauff, the seventh-seeded American, defeated Britain’s Emma Raducanu, while Madison Keys, the tenth-seeded American, defeated China’s Wang Xinyu by scores of 6-3, 6-2.
Elena Rybakina, the Wimbledon winner, advanced as well after winning in just 59 minutes over Slovene Kaja Juvan, 6-2, 6-1.
However, Sloane Stephens and Bianca Andreescu, who had previously won the US Open, also fell short. American Stephens was defeated by Anastasia Potapova of Russia 7-6 (7-2) 6-4, and Canadian Andreescu was defeated by Cristina Bucsa of Spain (a qualifier) 2-6 7-6 (9-7) 6-4.
Rain forced a six-hour delay in play on the outdoor courts, with late-night matches being played to make up for the scheduling disturbance after heavy rains earlier forced postponements on day two.