Arthur Fils has suffered a worrying injury blow as he was forced to retire during his quarter-final match with Taylor Fritz at the 2026 Swiss Indoors.

The world No 8 retired due to a back injury when trailing 2-6, 0-2 against 13th-ranked Fritz at the ATP 500 tournament in Basel.

After falling 2-5 behind in the opening set, a concerned-looking Fils left the court to receive treatment after a lengthy discussion with the trainer.

The injury appeared to surface early in the match, and it is a real concern after Fils’ 2025 season was cut short by a stress fracture in his back.

It is unclear whether Fils will be fit to compete at next week’s Paris Masters, or at next month’s ATP Finals — which he is in a strong position to qualify for.

Speaking on Tennis TV after commentating on the match, Naomi Cavaday said: “It’s such a shame; it’s been a spectacular 2026 for Arthur Fils.

“But it’s a back problem that means he just cannot compete. Miles away from feeling good enough here, and with Taylor Fritz at the other end of the court, [he] just had absolutely no chance.

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“Well, we just hope that it is not a long-term injury, and that it’ll just be a few days… he can get himself back in action. Maybe back for Paris, but definitely back for Turin if he does confirm his spot there.

“It’s always really tough. Of course, six months out with the initial back stress fracture, you’ve gotta feel like it’s sensible that he doesn’t put it through anything unnecessary.”

Former ATP Tour player Gilles Muller confirmed Tennis TV had received information that Fils had “felt fine before the match.”

“It’s a bit heartbreaking. We saw yesterday [Flavio] Cobolli [retiring] in Vienna, now today Fils here in Basel,” Muller said.

“Just gotta hope it’s nothing serious. I think he made the right choice not to force it too much.

“We also have confirmation from our reporter on site that his team didn’t know what was going on — he felt fine before the match.

“But yeah, something must have happened there in the beginning of the [first] set. It didn’t look good. You could definitely see that he was not moving okay, he was low on energy, as well.”