Martin Laird and Patrick Cantlay are the players to catch in the PGA's Shriners Hospitals for Children Open in Las Vegas after opening up a two-shot gap on their nearest challengers.

Scot Laird and Cantlay both shot six-under 65s on Saturday to be 20 under for the tournament.

They lead from third-placed Americans Matthew Wolff, Wyndham Clark, Brian Harman and Austin Cook.

Wolff hit three back-nine eagles en route to a blistering 61, for the day's best round.

The 21-year-old, who also had four birdies in his bogey-free round, needed a birdie-birdie finish to card a 59 but could only manage par on the 17th and 18th holes.

Only 12 players have shot sub-60 rounds in PGA Tour history.

The shot that got Wolff's game going came on the par-four 11th when his 115-yard second shot from the fairway bounced past the flagstick only to spin backwards and into the hole for his first eagle.

Wolff remained frozen in his follow-through position after the ball disappeared into the cup before shaking his head and smiling.

"You never expect to hole-out, but when it happens, it puts you in a really good mindset," said Wolff.

"I was a little frustrated on the front nine ... then those three eagles propelled me to the top."

Wolff, who is gunning for his second win on the PGA Tour since turning professional last year, announced himself as a force in the golf world when he finished in a tie for fourth at the PGA Championship in August, his first major appearance.

He followed that with a second-place finish at the US Open last month.

Canlay expects the low scoring at TPC Summerlin to continue on Sunday.

"I'm sure by the time I get to the golf course the lead will already be more than 20-under," he said. "There's going to be a lot of birdies tomorrow."

Australia's Cameron Smith is six off the pace, tied for 19th, after shooting a four-under 66.

The Queenslander would have been closer to the lead had he matched his second round 63, which was possible amid ideal scoring conditions.

But he posted a double bogey on the par-four 10th after hitting his drive into the water, and a bogey on 12th.

Smith, however, bounced back with consecutive birdies on 13, 14, 15 and 16 to add to his ones on 3, 4, 7 and 9 to remain with a fighting chance.

Compatriot Matt Jones shot a third consecutive four-under 67, to be eight behind Laird and Cantlay.

Sydneysider Cameron Davis is three behind Jones after shooting 70.