Carlos Alcaraz into Buenos Aires semi-finals

World number two Alcaraz, playing his first tournament since a shock quarter-final exit at the Australian Open, came through 7-6 (7/1), 6-1.

Defending champion Carlos Alcaraz reached the semi-finals of the Buenos Aires clay-court tournament on Friday with a straight-sets win over Italian qualifier Andrea Vavassori.

Carlos Alcaraz, of Spain, celebrates a point during an Argentina Open ATP quarterfinal tennis match against Andrea Vavassori (AP)

World number two Alcaraz, playing his first tournament since a shock quarter-final exit at the Australian Open, came through 7-6 (7/1), 6-1 against his 152nd-ranked opponent.

Vavassori, who stunned three-time major winner Andy Murray on clay at the Madrid Masters last year, matched the Spanish star blow-for-blow in the opening set.

However, Alcaraz then raced into a 5-0 lead in the second set before sealing victory after an hour and 40 minutes on court.

"In the first set he played such a high level," Alcaraz said.

"It was really tough to return his serve and challenging conditions with the wind. But I think I played better in the second set.

"His level went down a bit, with his serve as well and I put some returns in, took my chances and I think that was the difference."

The 20-year-old Spaniard will face either Chilean third seed Nicolas Jarry or Argentina's Tomas Etcheverry, seeded sixth, for a place in Sunday's title match.

The other semi-final will be an all-Argentine affair with Facundo Diaz up against Federico Coria.