"He sneezed a lot": Alcaraz stumbles at the start of the ATP Finals

Spaniard loses opening match in Turin

Carlos Alcaraz, the world number one, lost his opening match at the ATP Finals in Turin on Sunday, going down 6-3, 6-4 to Italy's Lorenzo Sonego.

The 19-year-old Spaniard, who is making his debut at the season-ending tournament, was broken twice in the first set and once in the second as Sonego, ranked 45th in the world, claimed a surprise victory.

Alcaraz, who has won five titles this year including the US Open, had been struggling with a hamstring injury in recent weeks and admitted afterwards that he was not at his best.

"I didn't play my best tennis today," said Alcaraz. "I was a bit tired and I made too many mistakes. Lorenzo played very well and deserved to win."

Sonego, who is making his second appearance at the ATP Finals, was delighted with his victory.

"It's an incredible feeling to beat the world number one," said Sonego. "I played very well and I'm very happy with my performance."

Alcaraz will now need to win his remaining two matches in the round-robin stage if he is to reach the semi-finals.

He will face Felix Auger-Aliassime of Canada on Tuesday and Andrey Rublev of Russia on Thursday.

Sonego will face Rublev on Tuesday and Auger-Aliassime on Thursday.

The top two players in each of the two round-robin groups will qualify for the semi-finals.