Top seed Alexander Zverev suffered a shock exit from the Acapulco Open on Wednesday, falling in three sets to Serbia’s Miomir Kecmanović, who secured the first top-five victory of his career.

Ranked 84th in the world, Kecmanović produced a composed and resilient display to defeat the world number four 6-3, 6-7 (3/7), 7-6 (7/4) in a gripping two-hour, 35-minute contest. Zverev was playing his first tournament since a marathon semi-final loss to eventual champion Carlos Alcaraz at the Australian Open.

The 25-year-old Serbian had previously lost all 11 of his matches against top-five opponents, but showed little sign of nerves as he raced through the opening set. Zverev gradually raised his level and edged a tense second-set tie-break to force a decider, only for Kecmanović to hold firm in another breaker to seal a landmark win.

“It feels amazing,” Kecmanović said after the match. “Obviously he’s the big favorite, so I didn’t have any pressure there, but you still have to play well when it matters, close out the match — and thankfully it went my way.”

Zverev’s performance was hampered by a flurry of unforced errors, including 17 off the backhand wing, as the German struggled to find consistency in key moments.

The upset continues a chaotic week in Acapulco, with the tournament’s top four seeds all eliminated before the quarter-finals. Second seed Alex de Minaur bowed out on Monday, while third seed Casper Ruud exited on Tuesday. Fourth seed Alejandro Davidovich Fokina joined them on Wednesday after a straight-sets defeat to Italy’s Mattia Bellucci.

With the draw blown wide open, Kecmanović’s breakthrough victory now stands as the headline result of a tournament full of surprises.