NEW YORK (CBSNewYork/AP) — Second-seeded Ash Barty overcame a slow start and a shaky serve to survive a first-round scare on a packed opening day of the U.S. Open.

Barty, the French Open champion, amassed 36 unforced errors and got less than half her first serves in en route to a 1-6, 6-3, 6-2 victory Monday over 80th-ranked Zarina Diyas of Kazakhstan.

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The Australian lost the first set in a mere 28 minutes and did not begin to come alive until the match was knotted at 3-3 in the second. She went on to win nine of the last 11 games, ending the match when Diyas sailed a forehand long.

“I was happy with the way I was able to fight through after a pretty awful start,” Barty said. “Not the ideal start. Not the perfect start. But it is what it is.”

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Karolina Pliskova serves during her US Open women’s singles first-round match against Tereza Martincova on Aug. 26, 2019 in New York City. (Photo by Mike Stobe/Getty Images for USTA)

Barty’s match helped kick off an opening day slate that included eight former U.S. Open champions, including top-ranked defending champion Novak Djokovic, Roger Federer and Stan Wawrinka. The main event was the opening night match on Arthur Ashe Stadium, when Serena Williams took on Maria Sharapova at the U.S. Open for the first time.

Williams played nearly perfect tennis and beat Sharapova 6-1, 6-1 in a contest devoid of drama.

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Third-seeded Karolina Pliskova also struggled in her opener, overcoming 32 unforced errors to win her first-round match over Czech qualifier Tereza Martincova 7-6 (6), 7-6 (3).

And Kristina Mladenovic of France defeated No. 14 seed and 2016 U.S. Open champion Angelique Kerber 7-5, 0-6, 6-4. Kerber’s first-round loss follows second-round exits at both the French and Wimbledon this year.

In other results, No. 12 seed Anastasija Sevastova beat Eugenie Bouchard, a former Wimbledon finalist and top-10 player, 6-3, 6-3. Former Olympic gold medalist Monica Puig fell by the same score to Rebecca Peterson of Sweden. And Russian Ekaterina Alexandrova defeated 2011 U.S. Open champ Samantha Stosur 6-1, 6-3.

On the men’s side, seventh-seeded Kei Nishikori became the first player to advance when qualifier Marco Trungelliti had to retire with the 2014 U.S. Open runner-up leading 6-1, 4-1. Trungelliti, an Argentine playing in his first Grand Slam main-draw match since the 2018 French Open, suffered a rib and abdomen injury in the second set and got treatment on the sideline before calling it quits.

Another notable result came when 18-year-old American qualifier Jenson Brooksby downed perennial top-10 player Tomas Berdych 6-1, 2-6, 6-4, 6-4.

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(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)