South Africa's Branden Grace was closing in on his fifth win of the season at St Andrews.
After five holes of his final round in the Alfred Dunhill Links Championship the 24 year old from Pretoria remained four clear of Dane Thorbjørn Olesen and six ahead of the rest.
Grace, poised to move up from 12th to third on this year's Race to Dubai, sank a ten foot birdie putt on the opening green to reach 21 under and followed it with four pars in a row.
Olesen birdied the long fifth, while sharing third spot on 15 under were France's Raphaël Jacquelin and Swedish trio Fredrik Andersson Hed, Joel Sjöholm and Alex Noren.
After graduating from last winter’s Qualifying School, Grace cemented his place on The European Tour with back-to-back victories on home soil in January.
His win at the Volvo China Open in March proved that was no fluke, and he won on the Sunshine Tour only a week ago.
Grace was aiming to become the first Qualifying School graduate to win four times on The European Tour in the next season.
Grace's lead suddenly shrank to one when he bogeyed the seventh after coming up short of the green and Olesen, winner of his first European Tour title in Sicily in April, birdied the next two.
They were 20 under and 19 under respectively, with Scot Stephen Gallacher, winner in 2004, joining Noren two further back with five birdies in six holes from the fifth.