Carlos Alcaraz made a triumphant return to the world's pinnacle on Saturday, dispatching compatriot Albert Ramos-Vinolas with ease in his inaugural appearance at the Italian Open amid the unfortunate truncation of play due to inclement rainfall.
In-form Alcaraz ensured the top spot by taking to the court to play his second-round match in Rome as he seeks a third straight tournament win.
The 20-year-old, who saw off Ramos-Vinolas 6-4, 6-1, will overtake Novak Djokovic as world No. 1 and is assured of the top seeding at the French Open later this month.
He came through in a match that started several hours late due to the pelting rain which drenched the Italian capital.
"The conditions here weren't easy, the rain, the waiting all day, not knowing if I would play. It was tough," said Alcaraz.
He added, "For me, it doesn't change too much to be No. 1 or 2 seed. I focus on the tournament and my game."
The Spaniard became the youngest-ever world No. 1 thanks to his United States Open triumph last September, with Djokovic denied entry to the U.S. because of his COVID-19 vaccination status.
Alcaraz will begin his 23rd week at world No. 1 on May 22.
The second seed arrived in the Italian capital on a fine run after back-to-back clay court titles in Barcelona and Madrid, and he made short work of Ramos-Vinolas.
He took control of the match in what turned out to be the final game of the first set, breaking Ramos-Vinolas to take the lead in what had been a hard-fought match up to that point.
From there, Alcaraz went through the gears, unleashing a vast repertoire of shots that left Ramos-Vinolas deceived and set up a third-round clash with either Jiri Lehecka or Fabian Marozsan.
Fifth-ranked Stefanos Tsitsipas was set to join Alcaraz in the third round as he led Portugal's Nuno Borges 6-4, 4-3 when play was halted for the day due to another downpour.
The Italian Tennis Federation said that play would restart at 11 a.m. local time (09.00 GMT) on Sunday, meaning Daniil Medvedev and Alexander Zverev were left waiting for their opening matches.
Osorio stuns Garcia
Caroline Garcia became the fourth top 10 player to be dumped out of the women's tournament after the world No. 4 lost 6-4, 6-4 to outsider Camila Osorio.
Qualifier Osorio almost broke down in tears after her shocking straight-sets victory in a match that started two hours late and was interrupted for more than an hour at the start of the second set.
The career-best win for world No. 100 Osorio puts her in the last 16 of a WTA 1000 event for the first time.
She will face Beatriz Haddad Maia in the next round.
"I have no words to describe what I'm feeling right now," said Osorio on court.
"I've been struggling a little bit with my injuries, and now that I'm back playing and beating the No. 4 in the world, I can't believe it.
"I'm just super happy and proud about how I managed to stay calm and finish the match."
Garcia joins world No. 2 Aryna Sabalenka, third-ranked Jessica Pegula, and world No. 7 Ons Jabeur in being dumped out of the tournament.
World No. 6 Andrey Rublev was one of the few lucky ones to escape the early rain, defeating Alex Molcan 6-3, 6-4.