Martin Adams continued his march towards a third successive BDO World Championship title at Frimley Green with victory over Gary Stone.
Adams, the top seed and playing in a record 19th World Championships, was in a class of his own as he beat debutant Stone 4-0 to reach the last eight.
Earlier, 2009 runner-up Tony O'Shea, the eighth seed from Stockport, saw off Scot Ross Montgomery 4-1.
And debutant Wesley Harms of Holland beat England's Robbie Green 4-1.
Harms now faces Paul Jennings, who saw off fellow Englishman Steve Douglas 4-2.
Adams struggled to score heavily - he averaged a little over 90 - but his clinical finishing ensured that Stone never had a look in.
"I know there are a lot of shaky bits in my game," said Adams. "I've still got a little bit of work to do but I'm pleased.
"I'm just taking it game by game, round by round. Hopefully there will be players to push me and that's when I'll find out if I've still got it."