Sebastian Munoz leads by one at AT&T Byron Nelson

McKINNEY, Texas — Sebastián Muñoz will be the “other” local guy in the final pairing of the final round of the AT&T Byron Nelson.

RELATED:Leaderboard | Inside the Field: PGA Championship

It's cool by the Colombian who now calls the Dallas area home and has at least shared the lead after all three rounds.

Muñoz shot a 6-under 66 on Saturday and was 21 under, a stroke ahead of hometown favorite Jordan Spieth, who is still seeking a breakthrough at the event in which he contended in the final round as a 16-year-old high schooler in 2010. Spieth shot a 64.

Joaquin Niemann will be the third player in the final group Sunday, alone in third another shot back after a 65. James Hahn almost matched Muñoz's opening-round 60 at TPC Craig Ranch, shooting 61 to jump 34 spots to a tie for fourth with Justin Thomas (64).

Spieth is a year younger than Muñoz at 28 but has three majors among 13 career victories after starring at the University of Texas. Muñoz, who played in college nearby at North Texas, is 2 1/2 years removed from his lone PGA TOUR win.

“Besides winning in Bogota, Colombia, I've never been the favorite of any other place,” Muñoz said. “So it’s a familiar spot. Jordan is, of course, the golden boy here, so everyone’s favorite. I’m good friends with him, so it’s going to be a lot of fun tomorrow.”

Spieth never went more than two holes without a birdie before a bogey at 15. He's had lower rounds and been close to victory before in a tournament he wants to win badly after such a remarkable PGA TOUR debut as an amateur 12 years ago.

Besides, he and others among the top 30 in the world playing this week are getting ready for the PGA Championship next week at Southern Hills in Tulsa, Oklahoma.

“So having a chance to win this event, this will be kind of the best chance I’ve maybe ever had going into Sunday,” Spieth said. “Done a good job not putting too much pressure on myself, I just wanted to get into contention and obviously see what needs to be sharpened for next week. But there’s no better prep for a major than winning the week before.”

Speith was ninth last season in the first year at TPC Craig Ranch, his best Nelson finish.

Muñoz made a 39-foot birdie putt on the par-4 second hole and sank a long bunker shot on the short par-4 sixth.

Playing with another Texan in Ryan Palmer, Muñoz ran into trouble along with Palmer on the par-4 16th.

After Palmer sprayed his approach way right into the stands, Muñoz went left playing a shot from a bunker with the ball in the rough above his feet. He swiped the ground with his club after leaving a chip 30 feet away and ended up with his only bogey.

Palmer, two shots back at the time after a stretch of five consecutive birdies, had to drop in some deep rough, needed two shots to get out and three-putted for double-bogey.

A West Texas native and Dallas-area resident seeking his first individual victory since 2010, Palmer shot 70 and was 17 under with defending champion K.H. Lee (67) and 2011 Masters winner Charl Schwartzel (68).

Spieth briefly pulled even with Munoz at 18 under with five birdies in six holes before the Colombian hit his approaches on 9 and 10 within 5 feet for birdies that put him back in front to stay.

Hahn missed the cut the past two times he played the Nelson after finishing third in 2017, the last year at the TPC Four Seasons in another Dallas suburb, Irving.

The move to McKinney, about 30 miles north of downtown, came after the Nelson was played twice at Trinity Forest in southern Dallas, then canceled during the pandemic before another relocation.

A two-time PGA TOUR winner, Hahn birdied five of the last six holes on the front nine and started a 5-under stretch over four holes by hitting his second shot to 7 feet on the par-5 12th.

“I feel like it just played easy out there for me, but everyone’s shooting, 9-, 10-under, someone is every day,” said Hahn, who has missed 10 cuts this season. “So I just felt like, ‘Why not me?’”

Masters champion Scottie Scheffler, who overcame a triple-bogey early in the second round for an outside shot to make a Sunday run, recorded birdies in bunches in a 65 that left him at 16 under.

The top-ranked player and Dallas resident birdied four of the last five holes on the front and three in a row on the back, but his bogey-free round ended with a disappointing par on the reachable par-5 18th.

“I haven’t really seen the ball go in very much, which is frustrating because you got to make putts out here to shoot low scores,” Scheffler said. “I fought my way kind of back into the tournament, but I need a hot putter tomorrow if I want to make some noise.”

Davis Riley shot 64 and was tied with Scheffler and Beau Hossler (67).

A pair of older TOUR rookies faded from contention with 2-over 74s. David Skinns, a 40-year-old from England started the day tied for the lead with Muñoz and Palmer, and 33-year-old American Justin Lower, who was just a shot back.