Roman Andres Burruchaga earned the biggest win of his career at the Plava Laguna Croatia Open Umag on Wednesday when he upset top seed Flavio Cobolli 6-2, 6-4 to reach the quarter-finals at the ATP 250 event.

The Argentine took full advantage of an error-prone performance from World No. 9 Cobolli, who was competing for the first time since reaching the Wimbledon quarter-finals. Burruchaga stayed in control from the outset, and finished having won 78 per cent (25/32) of his first-serve points and converted four of the seven break points he earned, according to Infosys ATP Stats.

“I think I played an excellent match,” Burruchaga said. “Flavio is a really good player. He just made the Roland Garros final. He is really confident. I think I played a really good game, probably one of the best matches of the year for me, so I am very happy for that.”

Burruchaga, the No. 67 player in the PIF ATP Rankings, has now earned all 13 of his tour-level wins on clay courts. Following the first Top-10 win of his career, the 24-year-old will face countryman and seventh seed Camilo Ugo Carabelli, who edged former World No. 10 Pablo Carreno Busta 3-6, 7-5, 7-5 to reach the quarter-finals.

In other action at the ATP 250 event, Daniel Merida also earned one of the biggest wins of his career Wednesday when he stunned third seed Tomas Martin Etcheverry 7-5, 6-4 in one hour and 35 minutes to advance to the quarter-finals. Earlier this year, World No. 82 Merida reached his first tour-level final at the ATP 250 event in Bucharest.

Second seed Alejandro Davidovich Fokina and fourth seed Matteo Arnaldi were also among those who booked their last-eight spots in Umag. Davidovich Fokina moved past Marco Trungelliti 6-4, 7-5 in two hours and six minutes, while Arnaldi outlasted Argentine Federico Agustin Gomez 6-3, 5-7, 6-3 in a two-hour, 34-minute battle. With the win, Arnaldi earned his first victory since advancing to his maiden major semi-final at Roland Garros.

Watch highlights from Arnaldi vs. Gomez in Umag

The Italian will next face Damir Dzumhur, who defeated Bolivian qualifier Juan Carlos Prado Angelo 7-6(2), 6-1 in one hour and 38 minutes. In the final match of the day, Alex Molcan advanced to the last eight after home hope Dino Prizmic retired in the third set. Molcan led 3-6, 7-6(5), 4-0 when the 20-year-old Croatian could not continue inside the Goran Ivanisevic Stadium.