Emotional Jiri Lehecka forced to retire in Madrid as Auger-Aliassime advances

The Czech, who ended Rafael Nadal's final appearance at his home tournament on Tuesday, was hit by a back spasm in the sixth game.

He sought treatment off court before attempting to carry on but he managed only three points before slumping to the court, picking himself up to shake hands with his opponent and then smashing his racket in tearful frustration.

It was a sad end to one of the best tournaments of the 22-year-old's career and means Auger-Aliassime progresses to his first Masters 1000 final, where he will take on seventh seed Andrey Rublev.

This is the third match of the fortnight that Auger-Aliassime has not had to complete, with Jakub Mensik also retiring and top seed Jannik Sinner withdrawing through injury ahead of their scheduled quarter-final.

"It's crazy," said Canadian Auger-Aliassime, who had been having a difficult season. "I don't know if it's ever happened to a player before.

"It's kind of a weird situation to be in on my part. It's never happened to me in my career so far, a withdrawal or a walkover or retirement of this sort, and back-to-back like this. I couldn't believe what was happening when I saw his back blocked on him.

"I feel really bad for him. I've had injuries myself, and we can all imagine how it feels to come out on a night like this, hoping to win to go through, having a battle with your opponent, and not being able to play. I have a lot of empathy for Jiri, and I can't do anything but try to prepare for Sunday."

Lehecka himself benefited from a retirement in the quarter-finals, with Daniil Medvedev pulling the plug after one set.

Rublev arrived in the Spanish capital on a run of four straight defeats but has hit form brilliantly and followed up one of the biggest wins of his career over Carlos Alcaraz by defeating Taylor Fritz 6-4 6-3.