Carlos Alcaraz marked his return to the world No 1 spot by comfortably beating Albert Ramos-Vinolas at the Rome Masters on Saturday.
The in-form Spaniard ensured top spot just by taking to the court to play his second-round match in his first appearance at the Rome tournament as he seeks a third straight tournament win.
The 20-year-old, who saw off countryman Ramos-Vinolas 6-4, 6-1, will overtake Novak Djokovic at the top of the ATP rankings and is now assured of top seeding at the French Open later this month.
He came through in a match which started several hours late due to the pelting rain which drenched the Italian capital for much of the early part of Saturday.
Coming off titles in Barcelona and Madrid, Alcaraz extended his winning streak to 12 matches and improved to 20-1 on clay this year and will now face either Jiri Lehecka or Hungarian qualifier Fabian Marozsan.
“The conditions here weren't easy, the rain, the waiting all day, not knowing if I was going to play or not. It was tough,” said Alcaraz. “I had to adapt my game really quickly to be able to get though.
He added: “For me it doesn't change too much to be number one or number two seed. I just focus on the tournament and on my game.”
Djokovic arrived in Rome with a five-point lead over Alcaraz, but as the defending champion the Serb will drop points during the tournament.
Alcaraz is not defending any points, and earns ten by beginning his opening match in the Italian capital, enough to put him on top of the rankings.
The Spaniard became the youngest ever world No 1 thanks to his US Open triumph last September, with Djokovic denied entry to the United States because of his Covid vaccination status.
In other second-round matches, sixth-seeded Andrey Rublev beat Alex Molcan 6-3, 6-4; J.J. Wolf eliminated 14th-seeded Hubert Hurkacz 6-3, 6-4; and Borna Coric rallied past Thiago Monteiro 4-6, 7-6, 7-6.
In the women's third round, Colombian qualifier Camila Osorio upset fifth-seeded Caroline Garcia 6-4, 6-4; Anhelina Kalinina beat Sofia Kenin 6-4, 6-2; and Wang Xiyu defeated Taylor Townsend 6-2, 0-6, 7-5.