Carlos Alcaraz says he is “heartbroken” after withdrawing from Spain’s Davis Cup Finals team because of injury.

World number one Alcaraz, 22, who was beaten by Jannik Sinner at the ATP Finals on Sunday, says he has been advised not to compete because of swelling in his right hamstring.

Spain face the Czech Republic in the Davis Cup quarter-finals in Bologna, Italy on Thursday.

Spaniard Alcaraz, who won the French and US Open titles this year to take his career Grand Slam tally to six, wrote on Instagram, external that playing for his country was the “greatest thing there is”, adding: “I’m going home heartbroken…”

World number two Sinner – the four-time Slam winner – and team-mate Lorenzo Musetti are both missing from Italy’s team, leaving Germany’s Alexander Zverev, the world number three, as the only top-10 ranked player at the eight-team finals.

The Spanish tennis federation said Alcaraz felt “physical discomfort” in the back of his thigh during the first set of his 7-6 (7-4) 7-5 final defeat in Turin by 24-year-old Sinner.

Alcaraz travelled to Spain’s training camp on Monday but medical tests revealed “significant muscle strain with marked edema” in his hamstring.

He secured the year-end world number one ranking last week after reaching the knockout stages of the ATP Finals with three straight wins.