Carlos Alcaraz will face Jaume Munar in the semi-finals of the Japan Open after Denis Shapovalov retired hurt from Saturday's last-eight matchup.

Alcaraz was leading 7-6 (7-3) 2-1 after 82 minutes on court in Tokyo, when Shapovalov appeared to sustain a hip injury while stretching to reach a forehand on the run.

The Canadian had initially had the better of a chaotic opening set that featured six breaks of serve, going 5-3 up and seeing a set point saved when returning at 5-4.

Alcaraz finally found his rhythm after a tense start to the tie-break, winning four straight points from 3-3 to take the only completed set, though he later admitted the victory did not come in the way he wanted.

"It's a shame that he had to pull out," Alcaraz said. "Going through to a semi-final like this is not the way I wanted, but sometimes sports are tough. 

"You have to accept it. Hopefully he's going to be able to play in Shanghai fully healthy."

Munar booked his own place in the last four by overcoming France's Kyrian Jacquet 6-4 6-2 earlier on Sunday.

Elsewhere, at the China Open, Alex de Minaur downed Andrey Rublev in three sets and Hubert Hurkacz eased past Karen Khachanov 7-6 (7-2) 6-2, with the two victors now set to face off for a place in the Beijing final.

Not the way we wanted it to end… 

Alcaraz advances to the SFs as Shapovalov is forced to retire with injury, recover well Denis  #KinoshitaJOTennis pic.twitter.com/reUepHoFQI

— ATP Tour (@atptour) October 4, 2026

Alcaraz and Munar book all-Spanish semi

Alcaraz would certainly have preferred to see off Shapovalov on his own terms, but the Spaniard – who won the Japan Open on his 2025 debut – is still perfect at the event, now holding an 8-0 record.

The seven-time grand slam champion has a 3-1 head-to-head record against upcoming opponent Munar.

However, Alcaraz will be aware of the challenge his compatriot could pose, having lost to him in the Marbella semi-finals way back in 2021, when he was a wildcard himself.

Munar is into his eighth ATP Tour semi-final, though that victory over Alcaraz remains his only success at this stage of an event.