Chez Reavie also posted a 9-under 63 and is alone in second place at minus-10.
Nicholas Thompson, second on the tour's money list, shot a 5-under 67 and is tied for third place with overnight co-leaders Jason Day (69) and B.J. Staten (69) and Tag Ridings (64), John Riegger (65) and James Driscoll (66). That group came in at 9-under-par 135.
Uresti began on the 10th tee Friday and promptly drained an 8-foot birdie putt. He holed a 10-foot par save at 11, then recorded back-to-back birdies at 12 and 13.
He closed his front nine with a flurry. Uresti sank a 20-foot birdie putt at 17, then pitched in from 30 yards out for an eagle at the par-5 closing hole.
Uresti's second nine was not nearly as good as his first. He did tap in a short birdie putt at the first, but parred his next two holes. Once again Uresti posted two birdies in a row, this time from the fourth.
He was unable to make any birdies from there, but does own sole possession of the lead.
'Being in the lead is always nice,' said Uresti, who won this year in Wine Country. 'I kind of felt a good round coming today, but you never know in golf.'
On Friday, Uresti needed only 24 putts, the product of hard work.
'I've been working hard on putting with Stan Utley since the Houston Open last year,' acknowledged Uresti. 'Everything is feeling really good right now...my short game is there for me this year.'
Brad Elder (69) and Dustin Bray (68) are knotted in ninth place at 8-under-par 136.
The 36-hole cut came at 3-under-par 141 and the Nationwide Tour's leading money winner, and two-time champion this season, Nick Flanagan, missed the cut by a stroke.