Five-time grand slam champion Maria Sharapova survived 46 unforced errors to beat Alexandra Dulgheru and reach the US Open third round.
Fifth-seeded Sharapova, out-of-sorts early on a windy Arthur Ashe Stadium court, pulled herself together to post a 4-6 6-3 6-2 victory over the Romanian world No.95 on Wednesday.
The reigning French Open champion will face either 26th-seeded German Sabine Lisicki or American wildcard Madison Brengle for a place in the round of 16.
Agnieszka Radwanska's US Open woes continued as China's Peng Shuai toppled the fourth-seeded Pole 6-3 6-4 to reach the third round.
Radwanska, a former Wimbledon finalist who counts this year's Australian Open among two other grand slam semi-final appearances, had hoped to make it past the fourth round at Flushing Meadows in her ninth attempt.
But the 39th-ranked Peng put paid to that, breaking Radwanska three times en route to the victory sealed with a backhand winner on her third match point - her 28th winner of the contest.
"She's tough to play," said Peng, who beat Radwanska at the same stage of the US Open in 2010. "I kept running, I fought. It was amazing.
"I will try to keep going," said Peng, whose best prior US Open showing was a round of 16 appearance in 2011.
In other early action, Sloane Stephens lost before the third round for the first time in four trips when upset by 96th-ranked Swede Johanna Larsson 5-7 6-4 6-2.
French 22nd seed Alize Cornet dismissed Slovakia's Daniela Hantuchova 6-3 6-3 to reach the third round - matching her best US Open run.
Hantuchova had won six of their nine prior encounters, including at the 2012 Olympic tournament.
But Cornet controlled this one, breaking Hantuchova four times en route to the victory in an hour and 22 minutes.