Elina Svitolina said she was looking for "motivation" when she asked the chair umpire for an update on her husband Gael Monfils' match during her comeback win in the US Open.

Svitolina recovered to win 5-7 6-4 6-4, setting up a third-round meeting with American third seed Jessica Pegula.

"I had to bring a different energy and was thinking about him," she said.

"I was just trying to get some little motivation from him and change my head because I was not playing my best."

Pegula, 29, continued her fine form on the North American hard-court swing with a 6-3 6-1 win over Romania's Patricia Maria Tig.

The consistent Pegula, who has reached the quarter-finals of each Grand Slam without going beyond the last eight, faces Ukrainian 26th seed Svitolina on Saturday.

Svitolina, who reached the Wimbledon semi-finals last month, having returned to the tour in April after giving birth in October, battled through a tight second set before racing into a 4-0 lead in the decider.

Russian Pavlyuchenkova responded by winning the next three games to set up a nervy finale but Svitolina won two tense service games to progress.

"It was a very tough match," Svitolina said. "I didn't play so well. I was up and down."

Elsewhere, Wimbledon champion Marketa Vondrousova eased through by beating Italian Martina Trevisan 6-2 6-2 - the Czech ninth seed's ninth Grand Slam win in a row.

Tunisian fifth seed Ons Jabeur, who lost to Vondrousova in the Wimbledon title match, showed her defiance to beat 18-year-old Czech Linda Noskova 7-6 (7-6) 4-6 6-3 despite continuing to show signs of illness.

Jabeur, also the runner-up at Flushing Meadows last year, was coughing throughout the match and during her post-match interview on court.

Russian 13th seed Daria Kasatkina fought back from a set and a break down to beat American opponent Sofia Kenin 2-6 6-4 6-4.

American Madison Keys, the 2017 runner-up, was similarly comfortable in brushing aside Belgian Yanina Wickmayer 6-1 6-2 in 54 minutes.

And second seed Aryna Sabalenka proved far too strong for Britain's Jodie Burrage in a 6-3 6-2 win.

Sabalenka too good for Burrage

Burrage backed up her run to the second round at Wimbledon this summer with another Grand Slam win against Russia's Anna Blinkova two days ago.

The British number two was rewarded with a match on Louis Armstrong Stadium but causing a shock against second seed Sabalenka was always likely to be tough.

The 24-year-old only conceded four break points to the Australian Open champion, but her opponent converted three of them to ease into the third round.

Sabalenka will face France's Clara Burel in the third round after she beat 25th seed and 2016 finalist Karolina Pliskova 6-4 6-2.