Britain's Cam Norrie is out of the Madrid Masters after a third-round defeat to Casper Rudd, while Rafael Nadal survived a scare to win a three-hour epic against Pedro Cachin.
Norway's Ruud cruised to an opening 6-2 set success in just 31 minutes, breaking Norrie three times as the Brit struggled to deal with the power he was facing.
The second set proved more even, as Norrie claimed the first break of serve, only for Ruud to respond quickly and then break Norrie a second time, wrestling back the momentum for an impressive 6-2 6-4 victory in the Spanish capital.
In front of an adoring home support, Nadal beat Argentina's Cachin 6-1 6-7 6-3, recovering from a surprise second-set tiebreak defeat to win the crucial third set.
Ruud will next face Canada's Felix Auger-Aliassime in the last 16 stage, while Nadal will face the Czech Republic's Jiri Lehecka.
"I had good moments, some bad moments. I somehow found a way to get through," Nadal said afterwards.
"In the third set, even with some mistakes, I was able to be unpredictable and that changed the match. I'm enjoying playing, let's see how I wake up tomorrow.
"Playing at home means everything to me. Tomorrow is another day to keep dreaming and playing in front of this amazing crowd, that means everything to me."
World No 4 Daniil Medvedev dropped the first set against American Sebastian Korda but hit back to win 5-7 7-6 (4) 6-3.
He will face Alexander Bublik of Kazakhstan, who beat up-and-coming American Ben Shelton in three sets, in the last 16.
Earlier, Iga Swiatek remained on track for a first Madrid Open title with a comfortable 6-1 6-0 victory over Sara Sorribes Tormo.
The top-ranked Swiatek won the last 12 games of the match and dropped just five points in the second set, advancing to the quarter-finals in the only major European clay tournament the Pole has yet to win.
Swiatek, who lost last year's Madrid final to Aryna Sabalenka, will next face 11th-seeded Beatriz Haddad Maia, who defeated fifth-seeded Maria Sakkari 6-4 6-4.
Eighth-seeded Ons Jabeur also eased to a 6-0 6-4 win over Jelena Ostapenko.
Coco Gauff, bidding to become world No 2, lost to fellow American Madison Keys 6-7 (4) 6-4 4-6.
What's coming up on Sky Sports Tennis?
In the run-up to the second Grand Slam of 2024 - the French Open at Roland Garros from May 26 - you can watch all of the biggest tennis stars in action live on Sky Sports as they compete across the clay-court season.
- Internazionali BNL d'Italia in Rome (ATP and WTA Masters 1000) - May 7-19
- Geneva Open (ATP 250) - May 20-26
- Lyon Open (ATP 250) - May 20-26
- Internationaux de Strasbourg (WTA 500 with Emma Raducanu in action) - May 20-26
- Morocco Open (WTA 250) - May 20-26
How to watch play on Sky Sports Tennis
Sky Sports will broadcast more live tennis than anywhere else in 2024, including on its dedicated tennis channel, bringing over 4,000 matches from more than 80 tournaments a year on the ATP and WTA Tours, plus full coverage of the US Open exclusively live.
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Fans will also be able to follow their favourite players and gain deeper insights from both Tours via Sky Sports News, the Sky Sports App and skysports.com as well as via Sky Sports' social channels.
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