NEW YORK (AP) — Trailing big in the first round of the U.S. Open, Maria Sharapova thought  she’d pull through if she could push her inexperienced opponent to a third set. And Sharapova was right.

Shrieking as loudly as ever, Sharapova came back from a set and a break down against 19-year-old Heather Watson of Britain to win 3-6, 7-5, 6-3 on Monday, improving to 12-0 this year in matches that went the distance.

“It’s just a matter of belief within myself, that no matter how well or bad or good I’m playing, or my opponent is playing, I know I can tough it out,” the No. 3-seeded Sharapova said after her 2½-hour victory. “No matter what the situation is, I have the belief.”

Petra Kvitova. Fresh off that triumph, Kvitova — a 21-year-old from the Czech Republic seeded No. 5 in Flushing Meadows — failed to follow it up, flopping at the U.S. Open with a 7-6 (3), 6-3 loss to 48th-ranked Alexandra Dulgheru of Romania.

Venus Williams played her first match in two months and beat 91st-ranked Vesna Dolonts of Russia 6-4, 6-3.

“It’s always nerve-racking to play the first match after a layoff in a major. It’s not really my first choice at all,” said Williams, who pulled out of recent tuneup tournaments because of a virus.