Collin Morikawa had seven birdies in eight holes in the first 12 holes as he went five shots clear of the field in the World Golf Championships-Workday Championship at The Concession.
Then he made bogeys on two Par-5s and ended with 5-under 67, but still led by two shots. Morikawa was at 15-under 201.
Those on his heels were four-time major champion Brooks Koepka and Billy Horschel.
Koepka had a pair of bogeys early but with 70 and Horschel also had a late eagle on the par-5 17th hole and shot 69.
Rory McIlroy, who made a double bogey for the second straight day, was hopeful of getting to 10 under to at least give himself a chance. He did one better with a 66, including an eagle on the par-5 13th that gave so many players fits, and wound up just four shots behind.
Webb Simpson had a 69 and was three shots behind, followed by McIlroy and Patrick Reed (69).
Viktor Hovland holed out a wedge from thick rough 45 yards short of the green for eagle on No. 7 in his 66, which also had chipped-in for birdie from 80 feet on the par-3 14th. Hovland joined the group five shots behind at 206 that included Hideki Matsuyama (68).