Gerwyn Price and Michael van Gerwen suffered shock first-round defeats at the European Championship in Dortmund.
World number two Price lost 6-4 to Austria’s Rowby-John Rodriguez, 65 places below him on the PDC Order of Merit.
Rodriguez produced the biggest win of his career amid new health concerns over his daughter, who has suffered from heart problems.
“I’m shaking. I can’t believe I’ve beaten the world number two,” Rodriguez told ITV4. “I wasn’t coming because my daughter went back to the hospital two days ago.
“But a few hours before the game my missus told me they were back at home. So that was a big relief.”
Rodriguez secured victory with a 100 checkout and will meet world number one Peter Wright – who beat Ryan Meikle 6-2 – in round two.
There was another upset as Chris Dobey claimed a first career win over Van Gerwen, the world number three.
The Dutchman stormed back from 4-2 down to lead 5-4, but Dobey showed admirable composure to level and then take the deciding leg.
Dimitri Van den Bergh, the 2020 World Matchplay champion, was an impressive 6-2 victor over Irishman Daryl Gurney.
The first four legs were shared before the Belgian raced away to record a match average of 101.53.
Jonny Clayton beat local favourite Gabriel Clemens 6-4, while Portugal’s Jose de Sousa completed a comfortable 6-1 win over Martin Schindler.
Dave Chisnall averaged 107 to beat Stephen Bunting 6-0 and whitewash his fellow Englishman for the second consecutive time at a major tournament.
Bunting had failed to take a leg off Chisnall at the Masters in Milton Keynes at the beginning of the year.
Ross Smith booked a second-round date with Van den Bergh by rolling off four successive legs to defeat Masters champion Joe Cullen 6-4.