Carlos Alcaraz returned to the top of the ATP rankings on Monday after his Indian Wells triumph, while Rafael Nadal dropped out of the top 10 for the first time in 18 years.

The 19-year-old ended Daniil Medvedev's 19-match win streak with a 6-3, 6-2 hammering on Sunday to leapfrog Novak Djokovic, who is not competing in the U.S. hardcourt swing as he cannot enter the country due to not being vaccinated against COVID.

Carlos Alcaraz said his unwavering self-belief helped him come through an injury-plagued start to the season and drove his return to the top of the world rankings following his triumph at Indian Wells.

"I missed some tournaments I wanted to play, but I worked really hard with my team. I believe in myself and the work I'm doing right now and I'd say that's the most important thing.

"It means a lot to recover the number one ranking. I'm not going to say it was easy, but it was easier because Djokovic was not playing," said Alcaraz.

American Taylor Fritz dropped five spots to world number 10 after his title defence ended in the quarter-finals.

Nadal, who has been out injured since a second-round exit at the Australian Open, fell to 13th place.

The 22-time Grand Slam champion had previously been inside the top 10 since April 2005.