LOS ANGELES -- Dustin Johnson was determined to get off to a good start in the Northern Trust Open, so for the first time, he decided against trying to drive the 10th green at Riviera and instead laid up with a 4-iron.
He made par, which never hurts. And then he took off.
Johnson birdied three of his next four holes, one of them with a 65-foot putt, and he kept bogeys off his card during a cool, gentle morning for a 7-under 64 to build a one-shot lead Thursday over Andres Romero and Kevin Stadler.
"Had good vibes going all day, and just hit the ball really good all day long," Johnson said.
Romero had good vibes going for most of the day. The dynamic Argentine had eight birdies to offset a double bogey on the ninth hole when he didn't listen to his caddie. Romero finished with four straight birdies for a 65. Stadler had the best score among late starters, opening with a 30 on the back nine. He played the final eight holes in 1 over.
Brandt Snedeker, coming off a runner-up finish last week at Torrey Pines, and Ricky Barnes were at 66. Steve Stricker had a 67 despite a three-putt bogey at No. 3, missing his par putt from 2 feet when he couldn't get the sound of a nearby jackhammer out of his head.
Phil Mickelson thought he might be among the leaders. Going for an unprecedented third straight victory at Riviera, he was 3 under midway through his round. He finished with three bogeys over his last four holes -- the exception was a 6-foot birdie putt he missed -- and wound up with a 1-over 72.
"I had it right there with five or six holes to go, and I let it go," Mickelson said.
The wedge is approved for play under a legal settlement from two decades ago.
Couples was inspired by the fuss from last week, generated mainly by Scott McCarron saying it was "cheating" for players like Mickelson to use it. He also was impressed that Mickelson, given his stature as the top player in golf while Tiger Woods is away, was willing to take any criticism by using the club.
"I said, 'I think that's strong, and I'm going to use one next week," Couples said. "He said, 'Man, I think that's great.' I get out here and he's not using it."
Couples said the Ping wedge is the best one he has, although he suggested he would look at others as he played more tournaments.
Mahan said he never considered anything wrong with a club that was approved under the rules.
Mickelson's reason for using the wedge was to call attention to the USGA's process of changing rules, which he has referred to as "ridiculous." Mahan's reason was different.
"It spins a little bit more," he said.
Even so, it didn't help on the 10th hole, when Mahan went bunker-to-bunker and made double bogey. Heading down the 11th fairway, John Wood, his caddie who found the old Ping wedge, said with a laugh, "If we had V-grooves, we would have had to hit four times instead of three."
The par-4 10th hole is among the most famous in golf, and one of the best tests among short par 4s anywhere in the world. It measured 303 yards for the opening round, with an emphasis on angles more than how far the ball is struck.
Johnson is ample long, but this time hit 4-iron to about 85 yards, a safe wedge to some 18 feet and two putts for par.
"I didn't make birdie, but it was an easy 4," he said. "And I wanted it to be easy."
He made the rest of his round look that way. He was on or around the greens on two of the par 5s, received a gift with the monster putt on No. 12, and the only time he came close to a bogey was at the par-3 fourth, when he went long and chipped to 8 feet.
Romero, coming off such a poor year that he's not eligible for any of the majors, also had an easy time except for the ninth. From a fairway bunker, his caddie wanted him to hit 7-iron short of the green and get up-and-down for par.
"I'm so stubborn, I stayed with the 6-iron," Romero said. "And it buried in the bunker."
He took double bogey, then followed with his burst of birdies at the end. Romero tied for third at Riviera a year ago.
The field for the Northern Trust Open is 132 players, down from 144 players last year, because of a 30-minute loss of daylight. The tournament is being held two weeks earlier than last year. The Phoenix Open, which moved from early February to the end of February this year, will have its field increased from 132 players to 144 players. The field sizes return to normal when those tournaments resume their regular spots on the schedule. ... One week after his runner-up finish at Torrey Pines, Michael Sim bogeyed his last four holes and opened with a 77. ... Despite the shorter field, three players failed to finish. That included Rickie Fowler, who was 1 under playing the ninth hole.