Peter Uihlein surrendered the sole leadership as Bryson DeChambeau birdied four of the last six holes for a share of the lead at the Shriners Hospitals for Children Open in Las Vegas.
American DeChambeau fired a third-round 65 to join Uihlein at the top of the leaderboard on 16-under overall.
Uihlein, leader after the first two rounds, mixed a bogey and four birdies to get round in 68.
Lucas Glover followed up his opening 67 and second-round 70 with a 61 to move into third place and a shot off the leaders.
Starting on the back nine, the American had two eagles, the first on the par-five 13th before closing with another on the par-five ninth.
The shot of the day came from Chilean Joaquin Niemann who aced his 176-yard tee shot on the par-three 17th.
Former US Open champion Graeme McDowell moved into 27th on eight-under, while Scotland's Martin Laird shot an even-par 71, remaining on seven-under after 54 holes.