No.6 seed Lucie Safarova survived a scare from Sloane Stephens to advance to the fourth round at SW19.

The 2014 semi-finalist came from a set down to defeat the in-form Stephens 3-6, 6-3, 6-1.

At one set down and facing break point at 1-1 in the second, the left-handed Safarova fired a passing shot to hold serve and swing the momentum in her favour.

“It was important to hold that game and then I broke her right away after so that point probably turned around the second set,” Safarova said.

A finalist at Roland Garros in June, Safarova made an early exit at Eastbourne in the lead-up to The Championships, but has found her form on grass at SW19.

“It’s never easy to go from such a big event to right away the next Grand Slam but I think I’m doing quite well and fighting hard and I’m in the fourth round so I’m happy,” she said.

Safarova will next face American Coco Vandeweghe, who powered past No.22 seed Sam Stosur 6-2, 6-0. After dropping the opening two games of the match Vandeweghe turned on a 12-game streak to progress in just one hour.

The world No.47 landed 17 winners – 13 of them in the opening set – to charge into the round of 16 for the first time at a Grand Slam.

“It feels good, it’s not any feeling that I ever thought it would be,” Vandeweghe said.

“I kind of expected it would be like this whole crazy elation or something like that but I’m pretty calm about it, just going through my routine and sticking with that on and off the court and I think that’s what has kept me settled.”

Following a shaky opening set Stosur never gave herself a chance in the second, serving two double faults in her opening service game to go down an early break and firing 11 unforced errors in a forgettable 24 minutes on court.

Vandeweghe, whose only career title to date came on grass at ‘s-Hertogenbosch in 2014, has now won her past three matches against the Australian world No.23.

“I like what she brings out of me and my own game, I know what I’m going to get from her is a tough opponent and a tough competitor and a fighter, so I think that brings out my own competitive spirit and my own fighting spirit,” she said.

In the other upset of the day in the ladies’ singles draw, Kazakhstan’s Zarina Diyas overcame No.14 seed Andrea Petkovic 7-5, 6-4.

It was better news for No.30 seed Belinda Bencic, who survived a slow start to trump American qualifier Bethanie Mattek-Sands 7-5, 7-5.

Trailing 1-5 in the first set, Bencic finally found her range, helped along by Mattek-Sands’ mounting tally of unforced errors; 18 in the opening set to Bencic’s three.

Midway through the opener the American looked destined to oust another seed from the draw, two days after she eliminated No.7 seed Ana Ivanovic.

But the spirited world No.158 could not hold her momentum and the Swiss rising star, cheered on by compatriot Martina Hingis, found her rhythm against Mattek-Sands’ net-rushing style of play.

“I think the key was that I was getting more rhythm,” Bencic said.

“In the first set I was definitely thinking too much about her game and her always coming to the net and me panicking when she does it.

“I think I calmed down a little bit and I focused on my game and tried just to put the ball in the court and to make a rally and not to think what I will do when she attacks.”

Bencic will next meet No.23 seed Victoria Azarenka of Belarus, who edged out Frenchwoman Kristina Mladenovic 6-4, 6-4.