Watson’s 68 gave him a two-stroke lead over second-place Kevin Stadler at 15-under 198.
Watson’s big break occurred on the par-five 13th when his drive went into a desert bush and settled next to a burrowing animal hole that would have interfered with his swing, giving him a free drop.
“Right next to my ball was a burrowing animal hole and my club was going to hit it at impact,” Watson said. “It was big hole and the club would get caught on it. So, I got a free drop and could easily wedge it out.”
He hit a 150-yard shot to the fairway, followed with a wedge to the fringe and two-putted for par on the way to a two-stroke lead.
Without the free drop, he thought he could have played a shorter shot.
“I was looking at a 20- or 30-yard shot,” Watson said.
Mickelson, whose 72 dropped him to three-under 210, made a double bogey on the par-three No. 16, the 20,000-seat stadium hole where he “lost focus” thinking about throwing footballs into the crowd.
The defending champion half-shanked his tee shot left on the 128-yard hole. He followed with a weak flop shot into the bunker, blasted to eight feet and two-putted.
“My brother, who is the ASU golf coach, brought out some ASU footballs that I signed and threw out there,” Mickelson said. “I think it’s the last time I’m going to do that, because mentally I was thinking about throwing it a couple holes prior."