World No. 189 Alex Molcan stunned top seed Gabriel Diallo on Wednesday at the Tiriac Open presented by UniCredit Bank in Bucharest, where he earned a 6-2, 6-2 second-round win.
Molcan reached a career-high No. 38 in the PIF ATP Rankings in May 2022 but has spent the past two years outside the Top 100. The 28-year-old Slovakian, who won two ATP Challenger titles in 2025, reminded everyone what he was capable of against Diallo, grinding down the Canadian in 88 minutes to back up his first-round win against Matteo Arnaldi.
"I am very satisfied," Molcan said. "I knew it would be a tough match, he is a very good player. But I knew it was his first match on clay [this year], so I wanted to focus on my game because maybe he would struggle as it is his first time on clay in a long time. I managed my game very well. I was trying to focus on what I should do. I am really happy with how I played today."
Diallo, a quarter-finalist on clay in Madrid last year, is now 5-9 on the season, according to the Infoys ATP Win/Loss Index.
Molcan is competing in the main draw at a tour-level event for the first time since 2024 and will next play Mariano Navone after the Argentine beat Elmer Moller 6-2, 6-1. Navone, a former finalist in Bucharest, is into his first tour-level quarter-final since Buenos Aires in February 2025.
In other action, Damir Dzumhur set a quarter-final meeting with Botic van de Zandschulp. Dzumhur recorded an upset 7-6(1), 6-4 win against fourth seed Nuno Borges, snapping an 11-match losing streak against Top 50 opponents.
Dutchman Van de Zandschulp advanced to his second tour-level quarter-final of the season with a 7-5, 6-1 win against Alexander Shevchenko. With his victory, the 30-year-old levelled his Lexus ATP Head2Head series with Shevchenko at 1-1.
