Former Kaneohe resident and Castle High alum Dean Wilson had two birdies and five bogeys for a 3-over 74.

Harrington opened with three straight birdies. He ran off four in a row after making the turn, and even picked one up on the tough 15th hole when his 5-iron hit the pin and settled 4 feet away.

His only bogey came from a three-putt on the par-3 14th, and the Irishman had a reasonable explanation for that.

"At this stage, I'm feeling invincible," he said. "I didn't think I was ever not going to make birdie."

It gave him a three-shot lead over Mickelson and Briny Baird among the early starters, with Jim Furyk another shot behind on a spectacular day of sunshine and shotmaking on the storied course off Sunset Boulevard.

Mickelson is playing for the first time since 2001 at Riviera, where he has never had much success. But coming off a five-shot victory at Pebble Beach where he tied the tournament scoring record, he kept right on rolling with a bogey-free 66. He hit only six fairways, but the rough is negligible this week, and Mickelson wasn't off by much.

His only disappointment was being three shots behind.

"It's a little humbling to shoot what I thought was a good round and then get lapped," Mickelson said.

Vijay Singh started eagle-birdie, but a couple of late bogeys brought him a 68. Retief Goosen made only seven pars in his round of 71.

Mickelson played with Ernie Els, one of several international stars making their '07 PGA Tour debut this week. The Big Easy labored to keep the ball in the fairway, but escaped with enough clutch pars — getting up-and-down from 90 yards on his final hole — for a 69 that left him pleased, although tongue-tied.

He noted that Mickelson played "awful," then quickly corrected himself.

"Awesome. I think that's the word you use," Els said with a laugh.

For Harrington, call it blissful ignorance. He first saw Riviera a few years ago on his way to the Target World Challenge in December and loved it. But as he looked back over his round, he realized there were nuances to the course that he still hasn't learned, and was thankful he didn't pay for it in the opening round.

He played two practice rounds, and both times hit driver and a 6-iron on the 463-yard hole, traditionally one of the toughest. But with the fairways running fast and firm, he was stunned to his see his drive land in the narrow neck of the fairway, leaving him only a 9-iron into the green to within 4 feet.

"If I had known I was going to do that, I wouldn't have been hitting my driver off the tee," he said.

Ditto for the 434-yard fifth hole, where the fairway ends after about 280 yards and drops down a shaggy hill. Harrington's tee shot went 277 yards, leaving him another short iron to 10 feet for birdie.