US Open: Stefanos Tsitsipas jeered by fans for toilet break during second-round win over Adrian Mannarino

World No.3 Stefanos Tsitsipas has fired down a career-high 27 aces on the way to a 6-3 6-4 6-7(4) 6-0 win over second-round opponent Adrian Mannarino, but another protracted bathroom break drew jeers from the US Open crowd.

Greek Tsitsipas won all his first-serve points in the opening set, fired off 53 winners in the match to Mannarino's 26 and looked set for a straightforward win at Arthur Ashe Stadium, before the Frenchman won a third-set tiebreak.

Tsitsipas then retreated to the locker room for a bathroom break of more than seven minutes, leaving Mannarino to ask for some balls to be brought out, so he could stay loose for the fourth set.

Tsitsipas, who infuriated Andy Murray in the last round by taking a seven minute-plus break, was met with a chorus of boos from spectators when he returned and even as he served to start the set.

But the jeers had little impact on his performance, as he powered through the final six games to set up a third-round tie against Spanish teenager Carlos Alvaraz.

Tsitsipas says he was completely soaked with sweat after the third set and it was important for him "to feel refreshed".

The Roland Garros runner-up did not realise he had exceeded his previous career high of 22 aces in a match.

"I just felt very loose on my serve, my ball toss was very consistent," says Tsitsipas. "I didn't really think about it, that it was that many."

SLOANE OUSTS GAUFF

Meanwhile, experience has trumped youth, as former champion Sloane Stephens' deadly forehand sealed fellow American Coco Gauff's fate 6-4 6-2 in the second round of the women's draw.

The pair appeared evenly matched early on, but 17-year-old Gauff handed Stephens a critical break with a double fault on the last point in the ninth game and never regained the momentum from her 28-year-old opponent.

Sloane Stephens beats Coco Gauff at US Open.
Sloane Stephens beats Coco Gauff at US Open. Photo credit: Getty

In the second set, Gauff failed to convert the only break opportunity she had against the 2017 champion, who had eight forehand winners across the 1h 6m meeting on Arthur Ashe Stadium.

"The forehand was key today," Stephens says. "I wanted to come out here and really execute, and play my game."

Stephens won the last seven points, as she dominated from the baseline and took a two-break advantage into the final game.

Stephens got 84 percent of her first serves in across the match, while Gauff committed four double faults.

"Serving that high percentage for me is always really key, just because I can get into the points and I can start off aggressive with me dictating play, which is what I want to do," says Stephens.

The off-court friends hugged at the net after the match and Stephens heaped praise on the 23rd-ranked Gauff - a fan favourite at Flushing Meadows - who reached the quarter-finals at Roland-Garros earlier this year, the best Grand Slam performance of her career.

"I love Coco, I think everyone knows I love Coco," says Stephens. "I've seen her game really transition and change... I know there's going to be great things ahead for her."

In the third round, she faces either Anhelina Kalinina or 2016 champion Angelique Kerber, whose second-round match was postponed, due to inclement weather.

Reuters