Branden Grace saw his four shot lead cut to one by Thorbjørn Olesen as the South African chased his fifth win of the season at St Andrews.
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 as Olesen birdied the fifth to remain in touch.
However, the 24 year old’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.
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 had three-putted for par on the ninth and when he did the same for bogey at the short 11th he was level with Olesen.
There was a danger of yet another three-putt on the 348 yard next after driving to the fringe, but by making a ten footer for birdie he went one up again.
Olesen was the closer of the two putting for birdie on the 13th and 14th, but Grace holed from 12 and 14 feet and his playing partner missed from nine feet both times.
It meant the gap was three with four to play, while Noren had joined Olesen in second place after he also birdied the same two holes.