World number three Alcaraz's only tournament win this year came in Rotterdam in February.

Monte Carlo marks the start of his clay-court season and it a surface on which the 21-year-old has strong credentials, having won last year's French Open.

The four-time Grand Slam champion admits external pressure to replace the suspended Jannik Sinner as world number one has been affecting his form, but he begins in Monte Carlo with a different mindset.

Italian Sinner is serving a three-month doping ban from tennis.

"A lot of people are asking me, or are telling me, that I have the chance to become number one if Jannik is not playing," Alcaraz told a news conference on Sunday.

"So probably that pressure has killed me in some way."

The Spaniard said the ranking is no longer his focus, and he expects that to allow him to play more freely.

"I'm just thinking that I'm not able to become number one in the clay season, even if Jannik is not playing, I don't have the chance to do it," Alcaraz said.

"I think I'm too far from Jannik. So I'm just here and I realise that I don't have to think about it and just go there and play.

"That's my mindset right now."