Australian Matt Jones' second round eight-under 63 at the Shriners Hospitals for Children Open was only upstaged by Las Vegas local and joint leader Kevin Na's nine-under 62 on Friday (Saturday AEST).
Playing alongside Phil Mickelson at TPC Summerlin, Na eagled the par-five 13th and 16th holes and added birdies on the par-three 17th and par-four 18th to share the top of the leaderboard with Lucas Glover, 2017 winner Patrick Cantlay and Brian Stuard at 12-under 130.
Jones sits a stroke back at 11-under after his impressive round, while fellow Australians Cameron Smith and Adam Scott are not far behind on nine-under while Aaron Baddeley and amateur Jack Trent are at six-under after two rounds
Na, who won the 2011 tournament for the first of his three tour titles, made four long putts on the back nine, holing out from 43 and 35 feet for the eagles and 23 and 22 feet on the closing birdies.
"My putter was hot," Na said.
"I started with a 60-footer on the first hole, and I just kept making putts today. I hit a lot of good shots, too, but the putter was working."
Glover matched Jones' 63 round, making an eagle on the 15th, while Cantlay eagled the par-four 15th, driving the green and holing a 45-footer, in a 64.
Stuard shot 65.
First-round leader Nick Taylor followed his opening 63 with a 69 to top the group at 10-under.
Mickelson was eight-under, following an opening 65 with a 69. He missed the cut last week at the Safeway Open in his season debut.
Defending champion Bryson DeChambeau also was eight-under, shooting 68.
Joel Dahmen ended up at eight-under, too, settling for a 64 after playing the first 10 holes in nine-under.
Top-ranked Brooks Koepka missed the cut in his season debut with rounds of 70 and 71.
The first No.1 player in Las Vegas since Greg Norman in 1988, Koepka had stem cell treatment on his left knee Aug. 25 after the FedEx Cup ended.
"Everything I've worked on - I've worked on my wedges, trying to control yardages a lot, and they were spot on all week. And I was just a hair off. I'm not disappointed. I feel like I was very, very close," Koepka said.
His younger brother, Chase advanced to the weekend, shooting 66-69 in his fourth PGA Tour start.