The Holwell Sports Bowls Club ace knocked out his Scottish opponent on a tie-break to seal a place in Friday afternoon’s quarter-finals against the unseeded Scott Edwards.
The result also gained revenge over the five-time champion after losing their Scottish International Open semi-final clash in November, as Gillett eventually came through 5-4, 2-9, 2-0.
“We both weren’t at our best today, but a win’s win,” said the 48-year-old.
“Like our match in Scotland when Paul got over the line, but he didn’t play at his best there and I didn’t either.
Gillett added: “I’m as pleased as punch. I have played Paul on a number of occasions over the years and I’ve been second best quite a few times.
“It was two guys having a scrap on a green and luckily I came out on top.”
With many high-scoring matches of late at the International Arena, the first set bucked the trend as it was singles all the way.
Gillett always just had the edge as Foster, fresh from winning the Open Pairs title with Alex Marshall, struggled to repeat his usual form on the portable blue rink.
Despite grabbing a one-set lead, Gillett found Foster a tougher nut to crack in the second set as the Scot inevitably produced a better standard of bowls and the Troon taxi proprietor comfortably ran out an easy winner to trigger a three-end lottery.
The momentum had swung Foster’s way and he looked the favourite to progress, but Gillett was having none of it.
After taking the first end, he then made sure he got in close on the second, with Foster resorting to what he described afterwards as a ‘hit and hope’ shot, but to no avail.
“I don’t think Les played his best today, but he didn’t have to,” added Foster.
“I played better in the second set, but it is very disappointing. I can play a lot better than that, but full credit to Les and good luck to him.”