Carlos Alcaraz was forced to quit his Paris Masters quarter-final on Friday with fears that an abdominal injury may derail the No. 1 with the ATP Finals starting in nine days in Turin.

The 19-year-old handed over a 6-3, 6-6(1) win to Hulger Rune, who has won  17 of his past 19 matches and stands a semi-final victory away from his fourth consecutive Tour final.

He will square off on Saturday at the Bercy arena in a re-run of last Sunday’s Basel final where he lost to Felix Auger-Aliassime.

Alcaraz said an abdominal muscle problem left him unable to go on as he retired after  97 minutes on court.

“I have (to have) tests before Turin,” Alcaraz said. :I’m trying to be at the 100 per cent. 

“I cannot stretch, I couldn’t serve well, I couldn’t hit the forehand well. When I turn my body, I feel it.

“Playing like that with problems in my mind, it’s better to retire.”

Rune said: ““I thought it was a great match, unlucky for him. I think we both played very well and I was super focused.”