By Mark Lamport-Stokes
PACIFIC PALISADES, California (Reuters) - Former champion Bubba Watson charged into an early share of the lead at one of his favorite venues while Rory McIlroy also flourished on his tournament debut at the Northern Trust Open on Thursday.
Left-hander Watson took advantage of a Riviera Country Club layout softened by overnight rain as he fired a five-under-par 66 in dazzling sunshine to join fellow Americans Chez Reavie and Luke List atop the first-round leaderboard.
Northern Irishman McIlroy, making his first PGA Tour start of the year, was one stroke back after mixing five birdies with a bogey to finish level with Americans Ricky Barnes, Charles Howell III and amateur Charlie Danielson.
South African Charl Schwartzel, one of the game's hottest players after winning twice in his last three starts worldwide, was among a group of seven bunched on 68.
Watson, who triumphed here in 2014, relished the softer conditions on an iconic layout which he has long revered.
"Today, obviously with the rain, it was easier," the twice Masters champion told reporters after a round highlighted by seven birdies. "The golf course is accepting shots. It's totally different than yesterday.
"I love it here because of the history. It's one of those golf courses where it can bite you at any minute but, at the same time, you can score and you can imagine a bunch of shots around the trees and around the greens."
McIlroy, like Watson a player who loves to picture shots in his mind before shaping them, was delighted to play well in his first competitive round at Riviera, which is consistently ranked by players as one of the top courses on the PGA Tour.
"Put myself out of position a couple of times but the way the conditions of the golf course were, it didn't punish you as bad as if it would have been as firm as it was the last couple of days," said the world number three, a four-times major champion.
"I felt like my pace on the greens was good ... and I lag-putted well. All of the things that you need to do around this golf course, I did pretty well today."
World number one Jordan Spieth, who tied for fourth in last year's Northern Trust Open, was among the late starters on Thursday.
(Editing by Frank Pingue)