Alcaraz is in a race against time to be fit for the French Open – where his rivalry with Sinner peaked in a sensational five-set final last year – after suffering a wrist injury at the Barcelona Open last week.

That has forced him out of this week’s Madrid Open, the biggest event in his home country, for a second-successive year, although he did make an appearance at the Caja Magica on Tuesday to sign autographs.

Sinner caught up with Alcaraz at the Laureus World Sports Awards, where the Spaniard was named World Sportsman of the Year, in Madrid on Monday night, saying: “I talked with him.

“We didn’t talk a lot about this topic. I think it’s also very, very private. But I think we all saw that he had a (cast) on – hopefully it can help him to get back as soon as possible.

“It’s a very big pity to not have him here and also Novak (Djokovic) – the two biggest stars in tennis.”

Alcaraz said on Monday of his prospects of playing in Paris: “I have a long career ahead of me. Forcing for Roland Garros could penalise me enormously in the future.”

Alcaraz’s absence is the most painful for the Madrid Open but it is another tournament that has been badly affected by withdrawals, with Djokovic still recovering from a shoulder problem, while British stars Jack Draper and Emma Raducanu have also pulled out.

“It’s for sure a very tough thing for the tournament,” said Sinner. “Also, last year, he (Alcaraz) didn’t play, so twice in a row and also Novak not here, it’s tough to swallow for a tournament.”

While he would no doubt relish another crack at his big rival after beating him in the final of the Monte-Carlo Masters earlier this month, Alcaraz’s absence means Sinner is a huge favourite to continue his winning run and extend his lead as world number one.

The Italian has no points to defend, having also sat out the tournament last year while he served his doping ban and is aiming to win a fifth-successive Masters 1000 title.

Sinner had talked after Monte Carlo about potentially also missing Madrid, but he said: “I feel quite good.

“I know in my mind that the most important is Roland Garros. We try to maximise to be in the best possible shape there.”

The Monte Carlo title was Sinner’s first on clay at Masters level or above and he is yet to make it past the quarter-finals in the Spanish capital, where the altitude makes it a unique event.

“I think every different kind of clay court can help me in trying to improve as a player and here definitely might be one of the most challenging ones,” added the world number one.

“I never played very well here. Let’s see how it goes this year, but I’m very happy to be here.”