Defending champion Michael Van Gerwen suffered his first defeat of this season's Premier League as Nathan Aspinall came out on top in Cardiff.
Aspinall averaged 101 and hit a 110 checkout in the third leg on his way to a 7-5 victory over the three-time world champion.
"I'm buzzing," Aspinall told Sky Sports. "This is my fourth game (in the Premier League) and I had not played well in any games so far. I just wanted to play my normal game and it's a massive win for me.
"The guy is human, you put him under pressure and he will miss darts. To beat the world number one, happy days."
Van Gerwen's defeat allowed Glen Durrant to move to the top of the standings thanks to a 7-4 win over Gary Anderson, while world champion Peter Wright raced into a 3-0 lead but had to hold off a determined challenge from Rob Cross to win 7-5.
Michael Smith took out finishes of 167 and 142 as he reeled off seven legs in a row to beat "Challenger" Jonny Clayton 7-1, while Daryl Gurney and Gerwyn Price drew 6-6, Price's third consecutive stalemate.
