NEW YORK — Naomi Osaka has moved into the fourth round of the US Open by getting past 18-year-old Marta Kostyuk 6-3, 6-7 (4), 6-2.
Osaka threw her racket after ceding the second set, then was one point from trailing 3-1 in the third.
But she saved five break points to get to 2-all, starting a five-game run that ended the match.
Osaka is a former No. 1-ranked player who has won two Grand Slam titles, including the 2018 US Open. The 137th-ranked Kostyuk was appearing in only her second major tournament.
No. 8-seeded Petra Martic advanced to the fourth round for the second straight year with a 6-3, 6-3 victory over Varvara Gracheva.
Gracheva made too many mistakes, with 33 unforced errors — three times as many as Martic.
As Gracheva’s deficit grew larger and larger, she knew more than anyone that a comeback was still possible. In the previous round, she trailed No. 30 Kristina Mladenovic 6-1, 5-1 and faced four match points before coming all the way back to win.
There was no such turnaround this time.
Martic now will try to get to the second Grand Slam quarterfinal of her career after reaching that stage at last year’s French Open.
She has lost her other six fourth-round matches at major tournaments, including against Serena Williams at the US Open last year.
Also moving into the fourth round: 2016 U.S. Open champion Angelique Kerber, who beat 20-year-old American Ann Li 6-3, 6-4.
Kerber’s next opponent is another American, 28th-seeded Jennifer Brady, a 6-3, 6-3 winner against Caroline Garcia.
In the previous round, Garcia upset top-seeded Karolina Pliskova.
Caty McNally, an 18-year-old from Ohio, eliminated No. 21 seed Ekaterina Alexandrova in three sets in a rain-delayed match to reach the third round.
McNally’s 4-6, 6-3, 7-6 (2) victory gives the host country 11 women in the third round at Flushing Meadows for the first time since 1992.
The match was suspended Thursday because of the weather. McNally, who plays doubles with 16-year-old American Coco Gauff, had never been this far in singles at a Grand Slam tournament.
