PHOENIX, February 2, 2014 (AFP) - Watson had shared the lead after each of the first two rounds of the $6.2 million US PGA Tour event. He finished 54 holes with a two-stroke cushion atop the leaderboard with a 15-under total of 198.
"I've got one more tough day, but what I'm seeing is building for the future," Watson said after a round that included four birdies and just one bogey. "It's coming together pretty good. I know that I can make some creative shots under pressure."
Watson was two strokes in front of Kevin Stadler, who fired a third-round 67 for 200.
Ryan Moore jumped into a share of third place on 201 with a seven-under 64. He was joined by Japan's Hideki Matsuyama, who posted a 68, and Harris English who carded a 69.
Brendan Steele notched the low round of the tournament with a nine-under 62 on the TPC Scottsdale's Stadium Course, moving into a tie for sixth on 202. He was level with overnight co-leader Matt Jones of Australia, who settled for a one-over-par 72, and Hunter Mahan (65).
English had joined Watson and Jones atop the leaderboard early in the round when he drained a 15-foot eagle putt at the third.
After Jones and Watson both birdied the third to move to 13-under, Jones three-putted for bogey at the fourth to hand the outright lead to Watson.
Watson rolled in a seven-footer for birdie at the sixth and picked up another shot at eight before he failed to get up and down from a greenside bunker at 10.
He added a last birdie at 17, where he sank an 11-footer.
"It was a struggle down the back nine, but I held it together, made some key putts and some key up and downs," Watson said. "I held it together. That's the part I like."
Stadler, meanwhile moved into second place with five birdies in his last six holes, while English's bogey at 18 cost him a share of second.
Jones was even for the day with two birdies and two bogeys through nine holes, but fell back with three bogeys in a row at 11, 12 and 13. A birdie at 14 was followed by a bogey at 15 before the Australian clawed his way back with birdies at 17 and 18.
Saturday's round drew a US PGA Tour record 189,722 fans.
Defending champion Phil Mickelson got into the spirit of the rowdy 16th hole, throwing American footballs into the massive gallery.
However, Mickelson admitted the gesture caused him to lose focus. He made a double-bogey on the par-three and was disappointed with his one-over 73.
Mickelson missed the green well left with his tee shot on the 128-yard hole -- then threw a few autographed Arizona State University footballs into the stands.
He then left his second shot short of the green, finally two-putting for a five.
"I just lost focus, and I think a lot of it was due to the fact that I have never done something like that on the 16th hole," said Mickelson, who was 12 shots off the lead. "I thought it was going to be fun, and it kind of took away my focus."