Uihlein capped another stellar round on the Old Course by chipping in from 47 yards out on the par-4 final hole to go 20-under 196 through 54 holes of the tournament, which is being played on three different courses around St. Andrews.
"It was not quite what I was trying to do, but it worked out," Uihlein said. "I carried it a bit too far, but got a bit lucky and it's pretty sweet, a cool finish and a great way to sign off."
The red-hot American had already wowed the Dunhill earlier in the tournament with a sizzling 60 Friday. He had a chance to score the European Tours first-ever round of 59 but his eagle putt on the final hole narrowly missed to the left.
Martin Kaymer, the 2010 winner of the tourney, shot 63 on the Old Course to grab a share of second place at 18-under 198. He was tied with Ernie Els, Joost Luiten, Richard McEvoy, David Howell and Shane Lowry, whose 64 Saturday equaled the course record at Carnoustie.
Sunday's final round takes place on the fabled St. Andrews course and features the top 60 players in the field.