"I usually have a tussle against Jason and thought I would be in for a hard match but he wasn't closing down heads and I finished comfortably," he said. "I opened with a treble on the first end and I found a line and length from my first bowl so was happy with my form."
Greenslade said: "Paul has set the bar for all the players to aim at and I just never matched him in any aspect of the game. Things haven't gone to plan off the green for me and I haven't been able to practice very much which meant I wasn't on my game and couldn't get a feel for the carpet."
Foster's opponent in the last eight tomorrow will be Mervyn King, who got the better of Irishman Jonathan Ross, who now lives in Paisley, 7-6, 4-14, 2-0.
Colin Walker, a qualifier from Pathhead, Midlothian, will be the only Scot in action today seeking a place in the quarter-finals tomorrow. He meets Ray Pearse, an Australian qualifier who beat Robert Weale, the former world and Commonwealth champion, in the opening round.
Norwich's Becky Field will contest the Women's World Matchplay singles title with Alison Merrien from Guernsey today, with the winner earning a place in next month's Co-operative Funeralcare International Open in Blackpool.