Dutchman Raymond van Barneveld stayed on track for another Lakeside World Championship title with a 5-0 win over compatriot Vincent van der Voort.
The 37-year-old, the winner at Frimley Green in 1998, 1999 and 2003, closed out the win with a superb 170 checkout - the highest possible.
Van Barneveld has yet to drop a set in his path to the semi-finals.
He will play Darryl Fitton in the last four after the fifth seed thrashed Scottish qualifier Robert Thornton 5-0.
"The 170 was a good way to finish," said Van Barneveld. "When I am so focused I feel like I can hit everything, and it was magnificent to win the game like that."
Fitton, a former British Open champion from Stockport, said: "I've been playing badly for the last few months, but it's all coming together now.
"I've been wanting to get this far ever since I lost to Andy Fordham at the
same stage last year."