Francisco Comesana stunned Australian Open finalist and world No. 2 Alexander Zverev on Friday with a 4-6, 6-3, 6-4 win in the quarterfinals of the Rio Open for the biggest victory of his career.

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

Friday’s win in Rio de Janeiro is the 24-year-old’s first victory over a top-five opponent.

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

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,” Comesana said. “I have to be grateful for this moment, and I am enjoying [it].”

Comesana faces Frenchman Alexandre Muller in the semifinals Saturday.