Two-time former champion Ted Hankey staked his claim to a third BDO World Championship title with a thrilling 4-3 victory over second seed Scott Waites at Frimley Green.
Hankey twice fought back from a set down in their second round clash to force a decider, and despite missing his first five match-winning doubles he finally checked out on 144 to claim victory.
Last year's beaten finalist Dean Winstanley was also the victim of an upset as he twice blew a two-set lead to crash 4-3 to Scotland's Alan Norris. Norris trailed 2-0 and 3-1 before fighting back to win.
Dutch 10th seed Willy van de Wiel fell 4-2 to Martin Atkins, who looked set to blow a 3-0 lead before finally repelling his opponent's brave comeback and sealing his win with double top.
But there was better news for the Netherlands as young debutant Christian Kist followed up his shock first round win over Jan Dekker with an impressive 4-2 success over Geert de Vos to book his place in the last eight.