The world number one was leading 6-4 2-1 in Rome when, with her left thigh also heavily strapped, she pulled out of the match following talks with a trainer.

Barty’s decision was precautionary as she will begin her French Open campaign in a little over two weeks’ time, bidding to regain the title she won two years ago.

The scare came just hours after world number three Simona Halep announced she tore a calf muscle this week, putting the Romanian’s Roland Garros prospects in some doubt.

Providing an update after the match with Gauff, which was interrupted by a rain delay, Australian Barty said: “The pain was becoming too severe.

”So, it was important to listen to my body and do the right thing, knowing we have a slam.”

Gauff, who had hit 12 winners to 15 unforced errors prior to her opponent’s withdrawal, will now compete in her first career WTA 1000 semi-final.

Karolina Pliskova remained on course for a second Rome triumph in three years, after saving three match-points to edge out Jelena Ostapenko.

The 2019 champion, who also finished runner-up last year, was 5-4 down in the final set when digging deep to hold off her 49th-ranked opponent.

The thrilling match went to a tie-break and Pliskova reeled off seven straight points after losing the opener to advance 4-6 7-5 7-6 (7-1).

“I’m just proud of how I fought,” Pliskova said at her post-match news conference. “I’m happy that I stayed in there and fought until the end.

“We played last month. So, I knew what was going to be happening. You can never get ready for some of the balls which she’s playing.”

Petra Martic stands between Pliskova and a place in the final for the third year running after the Croatian defeated Jessica Pegula 7-5 6-4.

Pegula eliminated Naomi Osaka earlier in the week but was second best against Martic, who progressed in one hour and 40 minutes.

Martic trailed 2-0 in the opening set before twice breaking Pegula to move 3-2 in front, but her opponent hit back to make it 5-5 in a tight contest.

However, Martic managed to break in the 11th game and served out the set, before showing her steeliness in the second to remain on course for a maiden WTA 1000 crown.(dpa/NAN)