Alcaraz, who turned 20 this month, captured the U.S. Open title in September to become the youngest man to top the world rankings. He will leapfrog Novak Djokovic into the number one spot again after the ongoing Italian Open.
He is also assured of top billing at the May 28th-June 11th French Open.
"It's great to be the number one seed at Roland Garros, in a Grand Slam, it's something crazy," Alcaraz said after his 6-4 6-1 victory over Albert Ramos-Vinolas in Rome on Saturday. "I wouldn't have believed it years ago, but yes, I'm very happy.
"It doesn't change too much to be the number one or number two seed - I just focus on the tournament, on my game, on every match, and that's something that I try not to think about.
"But of course, it's something great."
Alcaraz overcame an injury-hit start to 2023 and has already claimed four titles, including claycourt crowns in Buenos Aires, Barcelona and Madrid, to emerge as one of the top contenders for the trophy in Paris.
"I grew up a lot in a year," Alcaraz said of his meteoric rise. "I have more experience. I have played great matches. I grew up thanks to that a lot. I'm more mature as well.
"I would say in just a year I'm a totally different player. I read the match better than last year. I would say this year is totally different for me."
