Justin Thomas holds a one-shot lead after an eventful third round at the WGC-Mexico Championship that included Jon Rahm breaking the course record.
After scores of 67 and 66 over the previous two days, Thomas continued going in the right direction by signing for a 65 on Saturday, moving him to 15 under par.
The American started and finished his work with bogeys, yet in between had eight birdies to put himself clear at the top of a high-class leaderboard and in pole position for his third title of the 2019-20 PGA Tour season.
Erik van Rooyen and Patrick Reed head the chasing pack after both signed for 67s at the Club de Golf Chapultepec.
Van Rooyen had moved into contention at the halfway stage with a 62 that tied the course record – but Rahm went one better to climb to 11 under.
The Spaniard made a brilliant start with birdies at six of his first seven holes and following three more after the turn, he produced a stunning hole-in-one at the par-three 17th, his tee shot dropping into the cup on the second bounce.
"With the start I had today, the only thing in mind was trying to get as close as possible to the leaders," Rahm – whose solitary blemish during a spectacular day came at the eighth – said after the lowest score of his professional career.
"If I had a good finish, I was going to have a chance tomorrow, and that's kind of what gave me a second wind on the back nine."
Rahm is tied for fourth alongside Ryder Cup team-mate Rory McIlroy (68) and halfway leader Bryson DeChambeau, who followed up Friday's 63 with a 71 that included a double-bogey seven after finding water at the sixth.
Englishmen Tyrrell Hatton and Paul Casey are a further shot back on 10 under.