A hometown win for Jimmy Walker looks increasingly likely following the American's three-under-par 69 in the third round of the Texas Open on Saturday.
FedEx Cup leader Walker, who was born in Oklahoma but now lives in San Antonio, was in the 60s for the second consecutive day, moving four shots clear at nine under through 54 holes at TPC San Antonio, having teed off with a one-stroke advantage.
Walker - winner of the Sony Open and runner-up at the Tournament of Champions in 2015 - ended his round with back-to-back birdies to stay clear of countryman Jordan Spieth.
Spieth, who is eyeing his second PGA Tour title of the year after claiming the Valspar Championship a fortnight ago, faltered dramatically as he closed the penultimate round with a 71.
The 21-year-old Dallas resident had a double-bogey, two bogeys and two birdies from his final seven holes.
"I was getting a little too aggressive for this golf course, and it bit me," Spieth said afterwards.
A shot behind is FedEx Cup champion Billy Horschel, who ended his round with three successive birdies for a one-under-par 71.
Scott Pinckney (69), Chesson Hadley (71), Jason Kokrak (71), Zach Johnson (72) and Brendan Steele (72) are two under heading into Sunday's final round.
Chris Kirk (73) and Kevin Na (75) are eight shots off the pace, alongside Australia Aaron Baddeley (76).