Will Roger Federer withdraw from French Open 2021?

The 20-time Grand Slam title winner, who will be 40 in two months' time, battled over three and a half hours until 12:45 Sunday morning to reach the last 16 in Paris. He is due back on court on Monday to tackle Matteo Berrettini for a place in the quarter-finals.

However, having undergone two knee surgeries in 2020, the Swiss star admitted there are doubts he'll make it.

"I don't know if I am going to play," said Federer who was always likely to be playing his last French Open. "I have to decide whether or not to continue. Is it too risky to keep putting pressure on the knee? Is it a good time to rest?

If his knife-edge 7-6 (7/5), 6-7 (3/7), 7-6 (7/4), 7-5 win over 59th-ranked Dominik Koepfer was his last match in Paris, it will be remembered as a gripping affair on the court, but soulless off it.

As Federer weighs up leaving a tournament where Rafael Nadal and Novak Djokovic were always the title favourites, fellow veteran Serena Williams resumes her bid for a historic 24th Grand Slam title.