World number one Luke Humphries crashed out of the Cazoo Masters with a 10-7 defeat to Stephen Bunting in Milton Keynes.
Humphries, who won the World Darts Championship last month to move to the top of the rankings, failed to replicate his recent form when he fell to 16th-ranked Bunting.
Michael Smith exited in the final match of day, losing to Belgium's Dimitri Van den Bergh 10-6.
Michael van Gerwen held his nerve against Chris Dobey to cruise to a 10-4 victory.
The Dutch player hit double two to end defending champion Dobey's hopes of progressing in the competition.
Peter Wright sealed victory with double top to see off the spirited Krzysztof Ratajski 10-8, confirming his place in the last eight.
Briton Rob Cross fell short to Damon Heta, losing 10-8, but Nathan Aspinall was on form as he cruised past Dirk van Duijvenbode 10-5.
Dave Chisnall beat Danny Noppert 10-8 and Northern Ireland's Daryl Gurney saw off world number 12 Joe Cullen 10-8.
