Alan Norris was a surprise second-round victim as the second seed fell short in his bid to reach back-to-back BDO World Championship finals.
Norris, who was runner-up to Stephen Bunting last year at Frimley Green, was beaten 4-3 by fellow English thrower Darryl Fitton.
Fitton, who hit double eight at the third attempt to book a quarter-final place at Lakeside for the sixth time in his career, told BBC Two: "Alan was awesome when he got to the final last year. But I know I've got the game in me and it means so much to me because I'm still in the tournament.
"I thought I was going to miss that last dart because it was wobbling in the air. I hit the doubles at the important times."
Robbie Green cantered past Sweden's Peter Sajwani on a 4-0 scoreline to book a place in the last eight.
Three-time former BDO world champion Martin 'Wolfie' Adams raced to a 4-0 victory over New Yorker Jim Widmayer, dropping just two legs in the process.
Yorkshireman Brian Dawson did it the hard way, recovering from 3-1 adrift to win 4-3 and spike Latvian Madars Razma's hopes of a last-eight place.
Scott Mitchell wrapped up the day's oche action, reaching his first World Championship quarter-final by beating Belgian Geert de Vos 4-2.
