Daniel Berger retained his three-shot lead at the St. Jude Classic after firing a one-under 69 in the third round.
The American shot a 64 in the second round to move into the lead and sits at 10 under at TPC Southwind in Memphis, Tennessee.
Only a double bogey at the par-three 14th cost Berger an even bigger lead at the PGA Tour event.
He had four birdies and a bogey in his round to be in control of the tournament heading into Sunday.
Phil Mickelson (68) is among the chasing group at seven under.
The veteran American is joined by countrymen Steve Stricker (66) and D.A. Points (64).
Mickelson, runner-up in 2013, made birdies on holes five and eight before going through even on the back nine.
Points surged into contention thanks to a bogey-free round that included birdies on three, five, nine, 12, 13 and 18.
Sitting at six under are Colt Knost (67), Brooks Koepka (69) and South Korean Noh Seung-yul (67).
Boo Weekley, John Merrick, Harris English and Brett Stegmaier are a further shot back.
American Dustin Johnson, who opened with a 66, has slipped back into a tie for 18th.
He carded a three-over 73 in the third round to sit at two under overall.