YE Yang capped a sparkling round with back-to-back birdies as he fired a seven-under 64 to grab a share of the first-round lead at the Phoenix Open on Thursday.
The South Korean, who hasn't won on the US tour since he beat Tiger Woods at the 2009 PGA Championship, said a couple of mistakes early in the round helped him get focused for the back nine on the Stadium Course at TPC Scottsdale.
"I missed some good shots on the front nine so I was a little angry with myself, but I've been playing some solid golf the past four-and-a-half rounds. I think that's good," said Yang, who is tied with 2012 Masters champion Bubba Watson.
Play had to be suspended because of darkness with 10 players still on the course.
The former major winners were one shot ahead of Harris English, Kevin Stadler, William McGirt, Matt Jones, Chris Kirk, Pat Perez and Greg Chalmers.
A clutch of others including Hunter Mahan and Keegan Bradley were tied for 10th at five-under 66.
Defending champion Phil Mickelson posted an even-par 71 to sit among a large group of players tied for 65th place. Mickelson was forced to withdraw from last week's Farmers Insurance Open with back pain.
Yang shot 30 on the back nine, rolling in birdies on five of his final seven holes, including the 17th and 18th.
The 42-year-old began his round with a three-foot birdie putt at the first and got to two under with another birdie at the third hole.
He then three-putted for a bogey on the seventh after parring three straight holes.
That bogey allowed him to make the turn at one-under.
But Yang, Asia's first major winner, was just getting warmed up. He charged up the leaderboard on the back nine, getting it going with an 11-foot birdie putt at No. 10.
He then capped three straight birdies from the 12th with a 27-foot putt at the 14th to reach five-under before back-to-back birdies at the 17th and 18th launched him into the clubhouse lead.
Under ideal conditions, Watson was just as effective, making just one bogey and he birdied four of his last six holes to roar into contention.
"At the start of the day I wanted to be five-under. The scores look like a lot of people were making birdies, so around this golf course if you shoot five-under every day you are doing pretty well," Watson said.
"Somehow I got two better, so I guess tomorrow I can shoot two-under and be OK."
Mickelson was not looking for any excuses after a mixed day.
"My back is fine. My game was a little rusty," he said.
Leading first-round scores on Thursday in the $6.2m PGA Tour's Phoenix Open (USA unless noted, par-71):
64 - YE Yang (KOR), Bubba Watson
65 - Pat Perez, Kevin Stadler, William McGirt, Greg Chalmers (AUS), Matt Jones, Harris English, Chris Kirk
66 - Hunter Mahan, Keegan Bradley, Ryan Moore, Tommy Gainey, Jason Kokrak, Brendon de Jonge (ZIM), Brendan Steele, Hideki Matsuyama (JPN)
67 - Bryce Molder, James Driscoll, Sang-Moon Bae (KOR), Martin Laird (GBR), Erik Compton, Spencer Levin, Michael Putnam, John Mallinger, Graham DeLaet (CAN), Lee Westwood (GBR), Patrick Reed, Gary Woodland, Scott Piercy