Argentinian Francisco Comesana (24) stunned Australian Open finalist and world number two Alexander Zverev (27) on Friday with a 4-6, 6-3, 6-4 win in the quarter-finals of the Rio Open, the biggest win of his career so far.

Comesana, ranked 86th in the world, turned heads in his Grand Slam debut match last year when he handed sixth seed Andrey Rublev a first-round exit from Wimbledon.

Friday’s win in Rio de Janeiro is the Argentine’s first victory over a top-five ranked opponent.

“I was repeating to myself throughout the match, ‘How good it is to be alive,'” Comesana said in his post-match interview. “So, I was enjoying the entire match.”

Germany’s Zverev landed three aces as he won the first set, but Comesana fought back, converting two break points to win the second. Zverev struggled with his serve in the decisive set, making three double faults as Comesana took the win.

“I think it is because (of) all the hard work I have been doing to be here. I have to be grateful for this moment and I am enjoying (it),” Comesana said.

Comesana faces Frenchman Alexandre Muller in the semi-finals on Saturday.