NEW YORK: Former world No.1 Ana Ivanovic was the first major casualty of the US Open as the Serbian seventh seed fell 6-3, 3-6, 6-3 to Dominika Cibulkova in the opening match at Arthur Ashe Stadium on Monday.

The 50th-ranked Cibulkova of Slovakia seized the advantage with a service break in the fourth game of third set for a 3-1 lead and consolidated it with a backhand drop shot to make it 4-1 against the former French Open champion.

A backhand long from Ivanovic, who had her left foot taped midway through the final set, ended the nearly two-hour contest.

“Today I know that my game was there on the court,” said the 26-year-old Cibulkova, who cracked the top 10 last year before finishing the season ranked 11th and reached the quarterfinals last week in New Haven.

“I just had to stay tough and know I had to do it, she doesn’t give away shots.”

Cibulkova, a 2014 Australian Open finalist who earlier this year had Achilles-related surgery on her left foot, will next face American qualifier Jessica Pegula, a 7-5 6-3 winner over Belgian Alison Van Uytvanck.

For Ivanovic, the 2008 French Open champion, the result continued an up-and-down season. The 27-year-old Serb, who reached the semifinals at Roland Garros this year, was coming off back-to-back quarterfinals at US Open tune-up events in Toronto and Cincinnati.

She also has lost three times to players outside the top-100 this year, including twice at grand slams.

Other early matches on the women’s side went according to script as 13th-seeded Russian Ekaterina Makarova dismissed Brazil’s Teliana Pereira 6-3, 6-3 and 15th seed Agnieszka Radwanska of Poland crushed Czech Katerina Siniakova 6-2, 6-3.

Third-seeded Maria Sharapova withdrew from the US Open on Sunday because of a lingering right leg injury.

Mardy Fish won’t be retiring just yet.

The former top-10 player will stick around at the US Open for at least a couple of more days after winning his first-round match at what he says will be his final tournament.

Fish got a favorable draw against 102nd-ranked Marco Cecchinato of Italy, who was making his Grand Slam debut and is now 0-7 in tour-level matches.

Fish, whose has struggled with anxiety disorder, decided to wrap up his career at the US Open to try to make some new memories at his home Grand Slam tournament.

In 2012, Fish had to withdraw before his fourth-round match against Roger Federer because of a panic attack. He hadn’t played at Flushing Meadows since.

“I’m glad I got to come back here one more time,” the 33-year-old Fish said in an on-court interview after his 6-7 (5), 6-3, 6-1, 6-3 win Monday.

The American showed some nerves trying to serve out the first set, but otherwise Cecchinato looked overmatched. Fish requested to play on the Grandstand, the tournament’s third-largest court, where the fans can sit close and get loud.

He was cramping at the end of the nearly 3-hour match and said afterward it had probably been a couple of years since he had been on court that long. But he closed it out in style with an ace before Cecchinato could make things interesting.