Rafael Nadal reaffirmed his belief that compatriot Carlos Alcaraz is destined to have "one of the best careers of all time" in tennis. 

Alcaraz has won 18 ATP Tour-level singles titles since turning professional in 2018, a total which includes four grand slams and six Masters 1000 trophies. 

The 21-year-old is already one of the most successful Spanish players in the sport, with only Carlos Moya (20) and Nadal (92) winning more singles titles than Alcaraz. 

This season, Alcaraz has participated in seven tournaments, reaching three finals and winning the Rotterdam Open and the Monte-Carlo Masters for the first time in his career. 

Indeed, at 21 years and 337 days, Alcaraz became the youngest player to win the men's singles title in Monte-Carlo since Nadal (21 years and 321 days) back in 2008. 

He was denied a third Barcelona Open title after losing to Holger Rune in the showpiece match earlier this month, and withdrew from the ongoing Madrid Open through injury. 

Alcaraz is also only the third player since the format's introduction in 1990 to win 70 ATP Masters 1000 main draw matches before turning 22, after his win over Arthur Fils in Monte-Carlo.

He has since gone on to win six more matches, surpassing Novak Djokovic's 75 victories, but still finds himself way behind Nadal, who managed 110. 

For Alcaraz, the Italian Open is up next before the second grand slam event of the season takes place at Roland-Garros at the end of May. 

The world number three will defend his French Open title, a tournament well-known to Nadal, who won the event a record 14 times during his playing career. 

And the 38-year-old believes Alcaraz will win many more grand slams, while also backing him to become one of the greats of tennis. 

"All of us received the pressure from the media and from the hope that people have about you, but in the end, we are humans, and we know how to handle that," Nadal said.

"I don't think for Carlos it's a big deal holding that pressure. He's a great player and has a great family behind [him].

"I think he's doing great, and he's having an amazing career, and he's going to win much more if he stays out of injury – that's the most important thing.

"I wish, and I really believe that he's going to have one of the best careers of all time."