Roger Federer has pulled out of the French Open a day after winning a tough third-round match, opting to save himself for the grass-court season.
The Swiss star, who turns 40 in August, is targeting a record 21st grand slam title at Wimbledon later this month.
"After discussions with my team, I decided that I should withdraw from the French Open today," Federer said in a statement released by the French Tennis Federation on Sunday.
"After two knee operations and more than a year of rehabilitation, it's important that I listen to my body and not rush back into competition."
Federer, who has hardly played in the last 17 months because of a knee injury, suffered physically in his four-set, late-night victory over German Dominik Koepfer on Saturday.
He decided to end his Roland Garros campaign before a fourth-round match against Italian Matteo Berrettini.
Federer had said after Saturday's match that he was pondering whether to participate in the second week of the claycourt major as his season goal was Wimbledon, starting on June 28.
"We go through these matches ... we analyse them highly and look on what's next and we'll do the same tonight and tomorrow," he said.
"Because I need to decide if I keep on playing or not, or is it not too much risk at this moment to keep pushing or is this just a perfect way to just take a rest."
Meanwhile, second seed Daniil Medvedev's new love affair with clay continued to blossom as he marched into the quarter-finals with a commanding 6-2 6-1 7-5 win over Chilean 22nd seed Cristian Garin.
Medvedev, who has reached two grand slam finals on hardcourts but had never won a match in four previous appearances at Roland Garros, peppered the sun-bathed Suzanne Lenglen court with winners, especially from his laser-precise backhand.
The rangy Russian set up a mouth-watering clash against Greek fifth seed Stefanos Tsitsipas, who thrashed 12th-seeded Pablo Carreno Busta of Spain 6-3 6-2 7-5.
Asked if he thought this year's tournament would be the start of his French Open love story Medvedev said: "Hopefully... I hope that I can come many years in a row here, make great results, maybe win it one day."
Tsitsipas, who has won more matches on tour in 2021 than any other male, must overcome a 6-1 head-to-head record to Medvedev if he wants to reach a fourth grand slam semi-final.
"Of course, myself playing well, I feel like I don't have to think against who I'm facing or not, I just have to play my game, let the rest be witnessed," he said.
Meanwhile, sixth-seeded German Alexander Zverev reached his third French Open quarter-final by thrashing Kei Nishikori 6-4 6-1 6-1.
Zverev will face the unseeded Spaniard Alejandro Davidovich Fokina next.