Tournament host Danny Willett slipped seven shots off the pace after round three of the Betfred British Masters with Marcus Armitage leading the English charge.
Willett was unable to back-up his second-round 65 as he carded a two-over 74 on Saturday, with a double-bogey six on the 18th, which came about after he found the water with his second shot, dropping him to four under and into a tie for 17th place.
Thorbjorn Olesen is the 54-hole leader on 11 under par, with the Dane, seeking his first victory on the DP World Tour since the Italian Open in 2018, picking up three shots across his final two holes with an eagle at 17 and birdie at 18.
The eagle was the 32-year-old's second of the day as he also holed out from 120 yards on the par-four fifth at The Belfry, while his birdie at the last came as he sunk a 23-foot putt.
Olesen's three-under 69 leaves him three shots ahead of Armitage, whose third-round 70, which featured three birdies and a solitary blemish, took him to eight under for the tournament.
Hurly Long, who led the field after two rounds, is also at eight under after recovering late on to post a one-over 73.
The German dropped shots at the second, fifth, 11th and 12th before rallying to birdie three of his last six holes.
Scotland's Richie Ramsay is a shot further back on seven under but was one over for the round with struggles on the back nine stalling his progress.
Ramsay recorded two birdies in his first five holes but fell away later in his round, starting when he double-bogeyed the 12th.
The 38-year-old immediately picked up a shot at 13 but then bogeyed 16 and 18 to drop into a tie for fourth alongside a group of players including America's Chase Hanna, who shot a six-under, bogey-free 66 for the round of the day.
Ramsay's fellow Scot, Connor Syme, is at six under after carding a four-under 68 for the second day running.
Watch the final round of the Betfred British Masters live on Sky Sports Golf from 1pm on Sunday.