A 39th showdown between Rafael Nadal and Roger Federer will have to wait.
Citing a right knee injury, Nadal withdrew from the BNP Paribas Open on Saturday ahead of the scheduled semifinal match against Federer, the tournament announced.
Federer now has a chance to claim his 101st career ATP singles title on Sunday.
"I wanted to try my best to be competitive today," Nadal told reporters, including tennis writer Carole Bouchard. "But I warmed up this morning and felt that my knee wasn’t good enough to compete at the needed level."
Nadal isn't sure how severe the injury but has no doubt that he'll be ready for the Monte-Carlo Masters, beginning April 13.
After defeating Karen Khachanov in Friday's quarterfinal, the world No. 2 expressed some concern over his health and spoke about the physical toll of hardcourt tennis.
"I love to play on hard (courts), but probably my body don't love it that much," Nadal said, according to Christopher Clarey of the New York Times. "Less as I love. And my feeling is there is a lot of players that love to play on hard (courts), true, but their bodies don't love to play on hard, either."
Nadal is second all time with 17 Grand Slam singles titles but has been hampered in the past by knee problems.