Czech Tomas Berdych advanced to the semi-finals of the Monte Carlo Masters on Friday for a third time after Milos Raonic retired with a foot injury.
Raonic called a trainer after dropping serve for the second time to trail 5-2 in the first set.
Following a short discussion with the doctor, who had a close look at his strapped right foot, the big-serving Canadian went to see Berdych on the other side of the net to inform him of his need to retire.
Berdych, who lost to Rafael Nadal in the semi-finals in 2007 and was stopped by Novak Djokovic three years ago, will next face 14th-seeded Gael Monfils of France.
Monfils followed up his convincing win over Roger Federer in the previous round with a 6-1 6-3 defeat of ninth-seeded Grigor Dimitrov.
Berdych is yet to lose a set this week at the claycourt Masters tournament.
Later on Friday, an eight-time Monte Carlo champion Nadal will play fellow Spaniard David Ferrer, and top-ranked Djokovic will face Marin Cilic.
Monfils, who decided to play at the last minute this week after recovering from a right hip injury sooner than expected, was in control as he progressed to the semi-finals for the first time.
The Frenchman started strongly and dictated from the baseline to convert his three break points in a 24-minute opening set.
Dimitrov was better at the start of the second set but Monfils fended off two break points in the third game with consecutive winning serves, then held after a superb rally punctuated by a crosscourt winner just behind the net.
Monfils then broke for a 3-1 lead and sealed his win.
He has never gone this far on the Monte Carlo clay, with the third round his previous best performance.
The world No.18 broke an off-the-boil Dimitrov four times in what was a lacklustre performance from the Bulgarian, yet to fulfil his potential after being touted for several seasons as ready for a breakthrough.
Dimitrov was fresh from an upset defeat of defending champion Stan Wawrinka, a comprehensive win where he lost just three games against the Swiss.
“I had fun on the court and really tried to keep my concentration,” said Monfils. “But I’ve lost all but one match to Berdych.
“He’s playing very well right now and I have to reach my best on court.”