Spaniard Carlos Alcaraz returns the ball to British Cameron Norrie during the final of the ATP 250 Argentina Open in Buenos Aires on February 19, 2023. AFP
Reigning Rio champion Alcaraz, who returned last week after four months out because of injury, started his title defense at the clay-court tournament Tuesday.
However, he and Alves had their match interrupted by a torrential downpour with the 19-year-old Spaniard leading 6-4, 5-3.
Home-crowd favorite Alves, 22, who had pushed Alcaraz harder than expected Tuesday, looked determined to mount a comeback when play resumed on stadium court, winning the first game.
But US Open champion Alcaraz held serve in the second to take the match, 6-4, 6-4.
Alcaraz, who made his 2023 debut last week by winning his seventh career ATP title at the Argentina Open, will next face 86th-ranked Fabio Fognini of Italy Thursday in the round of 16.
"It was a complicated match, as the final result shows," said Alcaraz, who lost the first two games.
"Alves is a great player, which he showed here despite the conditions, having to stop and come back the next day. It's not easy to play like that. But I'm happy with the win."
Fognini, 35, beat Tomas Barrios of Chile in another rain-delayed match finished Wednesday, 6-2, 6-3.
"Fabio is a great player. He's played at a very high level his whole career," said Alcaraz.
"He's very dangerous, with huge talent, very explosive. I'll have to stay very focused."
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