Reigning French Open and Wimbledon champion Carlos Alcaraz’s participation in the ATP Finals in Turin has been cast into doubt after he pulled out of practice with illness.

His coach Juan Carlos Ferrera told Spanish media the 21-year-old cut short his session after just five minutes as a chest complaint was making breathing difficult.

Alcaraz is due to play Andrey Rublev on Wednesday.

Daniil Medvedev won his first indoor match since last year’s finals with a 6-2 6-4 victory over Alex de Minaur.

The 28-year-old Russian, who was docked a point for one of several outbursts as he lost his opening match to American Taylor Fritz, this time won without facing a single break point.

“I went into this match blocking the noise, even from myself,” Medvedev said afterwards.

“I really didn’t care what was happening on the court, I just tried to play, and it was a good feeling.

“After the last match, I was too tired mentally to fight the way I usually do. I went into the match (today) just trying to hit some shots, even thinking about next year.”

Britain’s Henry Patten and partner Harri Helioevaara are on the brink of the doubles semi-finals after a second straight win, beating Australians Max Purcell and Jordan Thompson 7-6 7-5 in a repeat of their Wimbledon final.

Top seed Jannick Sinner beat Taylor Fritz, his defeated opponent in the US Open final, 6-4 6-4 for his second win of the tournament.

“It was a very tough match,” said Sinner afterwards. “We got to know each other very well in a Grand Slam final. We knew exactly what to expect today, he was very aggressive and I was prepared.

“I just tried to serve very well in the important moments, which I did. That was a very crucial (seventh) game in the second set, I was down 0-30. If he breaks me there, the momentum could change.”