Belgium's Alexander Blockx continued his breakthrough run at the Madrid Open on Thursday, upsetting defending champion Casper Ruud 6-4 6-4 to reach the semifinals of a Masters 1000 event for the first time in his career.
The unseeded Blockx will now face second seed Alexander Zverev who swept aside Italian Flavio Cobolli 6-1 6-4.
Blockx had never won an ATP Tour-level match on clay before this month but he has thrived in Madrid, knocking out third seed Felix Auger-Aliassime en route to the last four.
Blockx wrapped up Thursday's victory in 96 minutes to become the fourth-lowest-ranked player to reach the semi-finals in the tournament's history.
There's a new kid on the Blockx 😉
— ATP Tour (@atptour) April 30, 2026
Alexander Blockx takes down the defending champion Ruud 6-4, 6-4 to reach his first Masters 1000 semi-final! @MutuaMadridOpen | #MMOPEN pic.twitter.com/ev6QZB8XHY
The world number 69 showed few signs of nerves as he dismantled Ruud with aggressive baseline play and solid serving.
"I'm proud of how I've played these past couple of matches. I think the conditions suit me well here," Blockx, 21, said in his on-court interview.
"I feel like it's clay which is slow, so I have time to settle and hit my shots, go for my shots.
"At the same time, it's quite fast with the altitude and the heat sometimes. I think it's the perfect combination for me."
Germany's Zverev was dominant from the outset against Cobolli, taking full advantage of the Italian's errors to race through the opening set.
The two-time Madrid champion was clinical throughout, firing 12 aces and committing just two double faults, while winning eight of 12 net points and finishing with 23 winners.
Zverev's victory comes just weeks after Cobolli knocked him out of the semi-finals of the Munich Open.
"No revenge, I love Fabio he's one of my favourite guys on the tour... This is sport, sport can change very, very quickly. I play an amazing first set, he didn't," Zverev said.