Tennis: Nadal withdraws from his Indian Wells semi-final against Federer with knee injury

Rafael Nadal withdrew from the BNP Paribas Open on Saturday, done in once again by a knee injury. He had been set to play long time rival Roger Federer in the semifinals. A sombre Nadal announced his withdrawal a couple hours before he was scheduled to take the court at Indian Wells Tennis Garden. "Still tough because I felt more or less OK during this beginning of the season in terms of my knee," Nadal said. The Spaniard's right knee flared up in the second set of his straight-sets victory over Karen Khachanov in Friday's quarterfinals. He twice called for a trainer, who applied tape just below Nadal's knee. Nadal said he won't play again until the Monte-Carlo Masters on clay in mid-April. "I don't have doubts today that I will be ready for Monte Carlo," he said.