Stephens even gets it done indoors under Ashe roof

Sloane Stephens doesn't betray much emotion on the court, so all of the double fist pumps at the conclusion of her U.S. Open match against former No. 1 Victoria Azarenka made perfectly clear just how tight and tense things had been.

Stephens, the defending champion and No. 3 seed, grabbed the last three games after returning from a brief break while the Arthur Ashe Stadium's roof was shut Friday and pulled out a 6-3, 6-4 victory over two-time runner-up Azarenka to reach the fourth round.

What helped Stephens after the 8-minute delay? "Just kind of refocusing," she said. Stephens went from up a set and a break at 3-1 in the second to down 4-3 when Azarenka took three games in a row. With light rain falling, play was halted while the cover was closed — although play carried on everywhere else, including the new Louis Armstrong Stadium, the only other arena at Flushing Meadows with a retractable roof. "The man upstairs waslooking out for me," Stephens said. "Unlucky for her."

When they resumed, she took control.

"I mean, of course it was a change of momentum. I won't be sitting here finding excuses; it's just what happens. You just have to accept (it)," said Azarenka, a former No. 1 who won the Australian Open twice and lost to Serena Williams in the U.S. Open final twice. "I just think from the tournament side, if they (are) expecting the showers, I think it might be better to just close the roof right from the beginning. I think it would just be smarter."

This was a match filled with lengthy exchanges and some fantastic shotmaking by both women.

Stephens was just a bit better, particularly on the most crucial points. She won half of Azarenka's 10 service games. And Stephens also made 10 fewer unforced errors, 27-17.

This is Stephens' sixth Grand Slam tournament since she had foot surgery in January 2017, and the other five followed a boom-orbust pattern: In two, she reached the final, including at the French Open in June; in the other three, she exited in the first round.

This time, the American will seek a quarterfinal spot when she faces No. 15 Elise Mertens of Belgium on Sunday.

Mertens, who beat Stephens at a recent hard-court tuneup tournament, reached the fourth round in New York for the first time by defeating No. 23 Barbora Strycova 6-3, 7-6 (4). The other fourth-round matchup in that quarter will be No. 7 Elina Svitolina against No. 19 Anastasija Sevastova.