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 eight birdies to offset a double bogey on the ninth hole when he didn't listen to his caddie. Romero finished with four consecutive 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.

Phil Mickelson thought he might be among the leaders. Going for an unprecedented third consecutive 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.

Mickelson took the Ping Eye2 wedge with square grooves out of his bag this week, although one wish was fulfilled when two players continued using it -- Hunter Mahan and Fred Couples, who had a 69.

The wedge is approved for play under a legal settlement from two decades ago.

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."

• Dubai Desert Classic: Rory McIlroy of Northern Ireland opened the defense of his title in Dubai, United Arab Emirates, with a 4-under 68 to share a six-way lead. Also shooting a 68 at Emirates Golf Club were Alexander Noren, Charl Schwartzel, Jeev Milkha Singh, Edoardo Molinari and Stephen Dodd. Tom Watson shot a 73 at his first tournament in Dubai.

• The PGA Tour and Synchro Sports have reached a three-year deal for a Champions Tour event at Fontainebleau Golf Club in Boisbriand, Quebec, Canada. The inaugural 54-hole Montreal Championship, featuring a 78-player field, will be played July 2-4 at the ClubLink course designed by Graham Cooke and Darrell Huxham.

Looking for more from the Post-Gazette? Join PG+, our members-only web site. You'll get exclusive sports content, opinion, financial information, discounts from retailers and restaurants, and more. Our introduction to PG+ gives you all the details.