Roger Federer plays a forehand during his men's singles third-round match against Dominik Koepfer at the 2021 French Open on Saturday in Paris. Photo: VCG

Roger Federer said Sunday he is considering withdrawing from the French Open despite reaching the fourth round as Novak Djokovic and Rafael Nadal set up clashes with two Italian teenagers widely seen as their Grand Slam heir apparents.

Two months shy of his 40th birthday, Federer, the 2009 champion, and probably taking part in his last Roland Garros, reached the second week for the 15th time.

His knife-edge 7-6 (7/5), 6-7 (3/7), 7-6 (7/4), 7-5 win over 59th-ranked Dominik Koepfer took place in Court Philippe Chatrier devoid of fans and atmosphere due to a government-enforced COVID-19 curfew.

Federer, who underwent two knee surgeries last year and is playing just his third event since the 2020 Australian Open, is scheduled to face Italy's Matteo Berrettini on Monday.

"I don't know if I am going to play," said Federer whose three-hour 35-minute tie ended just before 12:45 on Sunday morning.

"I have to decide whether or not to continue playing. Is it too risky to keep putting pressure on the knee? Is it a good time to rest?"

The 20-time Grand Slam title winner has always said Wimbledon is his priority this year.

He is chasing a ninth title at the All England Club where the action starts on June 28. 

He is also scheduled to play the warm-up grass court tournament in Halle beginning on June 14, the day after the French Open ends.

"Every match I have to reassess the situation and see the next morning in what state I wake up and how my knee is doing," added Federer.

Djokovic, the champion in Paris in 2016 and chasing a 19th Grand Slam title, brushed aside 93rd-ranked Ricardas Berankis of Lithuania 6-1, 6-4, 6-1. The world No.1 is in the last 16 for the 12th successive year and will next face 19-year-old Lorenzo Musetti.

Defending champion Nadal reached the fourth round for a record 16th time, claiming his 103rd victory in Paris to set a new record of match wins at a Grand Slam, eclipsing Federer's 102 at the Australian Open 

Nadal's 6-3, 6-3, 6-3 victory over Britain's Cameron Norrie put him into the last 16 of a major for the 50th time.

Nadal, chasing a 14th Roland Garros title and record-setting 21st Grand Slam, goes on to face Italian teenager Jannik Sinner.

Musetti, ranked 76 in the world, fired 50 winners past compatriot Marco Cecchinato in a 3-6, 6-4, 6-3, 3-6, 6-3 victory.

He becomes just the sixth man since 2000 to make the fourth round of a Slam on debut.

A lot of firepower 

Djokovic said he was a fan of Musetti with whom he practiced in Monte Carlo this year. "He's got a lot of firepower from both forehand and backhand," Djokovic said.

Nadal defeated Sinner in the quarterfinals in 2020 but expects a much tougher assignment on Monday.

Sinner, seeded 18, made it to the second week, easing past Sweden's Mikael Ymer 6-1, 7-5, 6-3.

Three top-10 women left

Barbora Krejcikova of the Czech Republic reached the last 16 for the second successive year with a 6-3, 6-2 victory over three-time quarterfinalist Elina Svitolina as only three of the top 10 women's seeds made it to the second week.

World No.33 Krejcikova goes on to face former US Open champion Sloane Stephens for a place in the quarterfinals.

Stephens, the 2018 runner-up in Paris, defeated Czech 18th seed Karolina Muchova 6-3, 7-5 to reach the last 16 for the seventh time.

Fourth seed Sofia Kenin, the runner-up in 2020 and the highest seed left, came back to beat fellow American Jessica Pegula 4-6, 6-1, 6-4.

The top three seeds, Ashleigh Barty, Naomi Osaka and Aryna Sabalenka all exited earlier in the week.

Defending champion and eighth seed Iga Swiatek overcame an early break to defeat Estonia's Anett Kontaveit 7-6 (7/4), 6-0 to stretch her record of straight-set wins at Roland Garros to 10 matches.

Swiatek reeled off 11 of the last 13 games and will next face Ukraine's Marta Kostyuk.

American 17-year-old Coco Gauff made the last 16 for the first time when compatriot Jennifer Brady retired with a foot injury after dropping the first set.