Sebastian Munoz signed for a second successive score of 67 to sit one shot clear at the end of the third round of the John Deere Classic.
The Colombian, who has had three top-10 finishes on the PGA Tour this year, had a trio of birdies and no blemishes on his card after the turn on Saturday, good enough to lift him to 16 under par.
Having held a share of the lead with Chesson Hadley at the end of the first round, Munoz is now just ahead of Brandon Hagy, who also carded a 67.
The 28-year-old will hope to hold off his competitors and add to his solitary tournament win on the PGA Tour, which came at the Sanderson Farms Championship in 2019.
However, on a condensed leaderboard, there are five players sitting well within striking distance on 14 under.
Adam Long (64), Cameron Champ (65), Kevin Na (66) and Ryan Moore (68) are all in the group along with Scott Brown, who burst into contention thanks to a 63 that included a run of six birdies in seven holes.
Overnight leader Luke List had managed the same score as Brown on Friday to move into first place, but his third round did not go quite so well.
After mixing three birdies with the same number of bogeys from the eighth hole onwards in an eventful run either side of the turn, List reeled off five straight pars to close out an even-par 71 that leaves him on 13 under.
American duo Maverick McNealy and Chez Reavie are on that same score, along with Venezuelan Jhonattan Vegas.