England's Conan Whitehead stunned eighth seed Cameron Menzies of Scotland to reach the second round of the British Darts Organisation World Championship.
The unseeded Englishman progressed by virtue of an impressive 3-1 win in an entertaining contest at the Lakeside Country Club in England's Frimley Green.
Whitehead kept cool under pressure, hitting a superb double 20 to finish the match and cause one of the upsets of the tournaments so far.
It proved to be a tough day for the seeded players in the men's event as Belgium's Geert de Vos and England's Jim Williams both needed five sets to reach the second round.
De Vos, seeded sixth, edged past compatriot Derk Teinekes 3-2 before Williams beat Sweden's Dennis Nilsson by the same scoreline.
Williams had to do it the hard way as he fought back from 2-0 down to keep his World Championship hopes alive.
Dutchman Richard Veenstra, the 11th seed, was also a 3-2 winner as he ousted Northern Ireland's Kyle McKinstry.
Veenstra's compatriot Aileen de Graaf enjoyed success in the women's event, taking place simultaneously alongside the men's, as she swept aside England's Paula Jacklin 2-0.
Russia's Anastasia Dobromyslova, the sixth seed, joined the Dutchwoman in earning victory today as she beat Anca Zijlstra of The Netherlands.
The tournament is due to continue tomorrow.