Casper Ruud's hopes of retaining his Madrid Open title were ended after losing to Alexander Blockx in straight sets in the quarter-finals.

Blockx won 6-4 6-4 in an hour and 35 minutes to reach his maiden ATP-level semi-final, where he will face either Alexander Zverev or Flavio Cobolli.

The 21-year-old made an impressive start in the Spanish capital, saving a break point before breaking to love in the third game.

The pair then exchanged breaks later in the first, before Blockx secured the lead with his fourth set point in the 10th game.

The second was more straightforward for the Belgian, who needed just one break of serve to win the set.

Ruud tried to force a third set, saving two break and match points on serve, only for Blockx to clinch victory a game later.

1 - Since 1990, Alexander Blockx is now the first Belgian to both defeat the defending champion and reach a maiden ATP-level semi-final at an ATP Masters 1000 event. Strong.#MMOPEN | @MutuaMadridOpen @atptour pic.twitter.com/K8KPHYWEmr

— OptaAce (@OptaAce) April 30, 2026

Data Debrief: Belgian history made in Spain

Since 1990, Blockx is now the first Belgian to both defeat the defending champion and reach a maiden ATP-level semi-final at an ATP Masters 1000 event.

Blockx (21 years, 14 days) is also the youngest player to defeat the defending champion at an ATP Masters 1000 event since Holger Rune (20 years, nine days) in Rome in 2023.

In the win, Blockx won an impressive 85% of his first-serve points (28/33) and 90% of his service games (9/10).