Published: Oct 02, 2011 12:33 AM EDT
Updated: Oct 02, 2011 6:30 AM EDT

LAS VEGAS (AP) - Nick Watney shot a 7-under 64 on Saturday for a share of the third-round lead with Kevin Na in the Justin Timberlake Shriners Hospitals for Children Open.

Watney, a two-time PGA Tour winner this year, birdied the final three holes and five of the last six at TPC Summerlin to match Na at 17 under in the Fall Series opener. Na followed his second-round 63 with a 66.

"I've driven the ball pretty well and it's just been fairly easy to hit quite a bit of greens," Watney said. "That's what you need to do out here is give yourself as many chances as possible. I've been able to do that so far.

"This course is right out there in front of you. It's fairly short for Tour standards, so it's just about execution."

He won the WGC-Cadillac Championship in March and the AT&T National in July.

Robert Garrigus (63) and Kris Blanks (66) were a stroke back, and Tommy Gainey (64), Paul Goydos (66) and Tim Herron (67) followed at 15 under.

Na, tied for the lead with Jhonattan Vegas and Charlie Wi after the second round, played the front nine in 4 under with five birdies and a bogey, and added a birdie on the par-5 16th to reach 17 under.

"I got off to a really good start on the front nine, made five birdies," Na said. "Unfortunately, I slowed down a bit and missed a few short ones. But to finish 5-under for the day, I was pretty pleased."

Robert Garrigus had nine birdies and a bogey in his 63. Hospitalized for dehydration on Monday in Phoenix, Garrigus opened the round with four straight birdies, then birdied three of the last four.

"I started off on fire," he said. "It was just one of those days when everything was going in early, and I knew if I could sprinkle in some (birdies) late it would be a really good day, and it ended up being nice."

Vegas (69), Roland Thatcher (63), Spencer Levin (64) and Carl Pettersson (66) were 14 under.

The 36-hole cut came at 4-under 138, with 80 players advancing. Because more than 78 players made the cut, there was a secondary cut at 4-under 209 after the third round to the low 70 players and ties.

The 4-under cut tied for the lowest on the PGA Tour this season with the Travelers Championship, John Deere Classic, Viking Classic and The Barclays.