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.
Also moving into the fourth round: 2016 US 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.
