Amanda Anisimova reached the fourth round of the French Open on Friday as Karolina Muchova retired late in their match through illness..

The Czech was unable to carry on due to her physical state, handing over a 6-7(7), 6-2, 3-0 win to the American.

Anisimova played a semi-final here three years ago as a teenager and has won 12 matches on clay this season.

She produced 43 winners and 36 unforced errors in the win which took two and a quarter hours with a first set which stretched for nearly 90 minutes.

Anisimova had to regroup after losing the marathon opener on the narrowest of margins after leading 5-1 in the tiebreaker.

“It’s very tough when you lose 7-6 with a couple of set points. I had to start over again, be positive and fight for it,” the winner said.

Anisimova claimed victory as her opponent held back tears before finally quitting the match.

The Czech who put out fourth seed Maris Sakkari in the second round, had her thigh taped in the first set and left the court after rolling her ankle at 2-2 in the second.

She came back on court and was broken immediately as the Czech’s condition failed to improve.