- Phil Mickelson cards an opening-round 65 to lead the Northern Trust Open
- The four-time major champion won his first PGA Tour event since April 2011 last weekend
- World No. 1 Luke Donald is four shots off the lead on one under par
- John Daly pulls out of European Tour event after injuring his elbow in opening round
Four-time major winner Phil Mickelson entered last week's Pebble Beach tournament without a PGA Tour success since April 2011, but now the American golfer has a chance for his second victory in a week.
In a sport where victors struggle to follow one title with another, the veteran left-hander made the perfect start to the Northern Trust Open in California as he claimed the early lead on Thursday.
Having carded a stunning final-round 64 to win the AT&T National Pro Am on Sunday, the 41-year-old fired an impressive five-under-par 65 despite difficult conditions at Riviera Country Club.
Mickelson handled the blustery winds on the Pacific Palisades course to open up a one-shot lead over Ryder Cup teammate Hunter Mahan and compatriot J.B. Holmes, while several players had yet to complete their opening rounds.
The highlight was his approach from nearly 300 yards at the par-five 11th which gave him an eagle chance.
Mickelson's attempt finished agonizingly short of the hole, but he was still able to recover and hole a birdie putt.
"I didn't think it was going to necessarily be reachable into that wind, but I was able to hit a low drive off the tee that scooted along the ground," he told the PGA Tour's website.
"I felt like if I could hit one more of those with a driver I could get right up by the green. I felt like it was worth the risk to try to scoop one up."
Mickelson, who won this event in 2008 and 2009, caught a lucky break on the 18th when his chip from behind the green found the cup for a sixth and final birdie of the round.
"It wasn't one I was really trying to make. It was quick, it was downhill, and I had to play about four or five feet of break, so it's not one that you're trying to get aggressive with," he said.
"I was trying to get good speed and try to let it feed with the break, and I got fortunate, obviously, that it went in."
Holmes, returning to the fold this year after brain surgery, bounced back from the third-round 80 that meant he missed the cut at Pebble Beach.
"It was really difficult. We got about four holes where the wind wasn't blowing. It was whipping most of the day on us," he said.
American Jonathan Byrd and Sweden's Carl Petterson were tied for fourth on three under.
South Korea's K.J. Choi, Spaniard Sergio Garcia and 2009 British Open winner Stewart Cink shot 69s to sit in an eight-way tie for sixth.
World No. 1 Luke Donald, his fellow Briton Justin Rose and 2011 U.S. Presidents Cup captain Fred Couples were all on one under after opening rounds of 70.
The 2011 PGA Championship winner Keegan Bradley, world No. 10 Dustin Johnson and 2007 Masters champion Zach Johnson were one shot further back.
Meanwhile, American golfer John Daly has pulled out of the European Tour's Avantha Masters in India after injuring his elbow during Thursday's opening round.
The two-time major winner completed a seven-over 79 after hitting a tree root with his second shot at the ninth hole, he confirmed on his Twitter website page.
"No bones are broken, possible torn ligaments according to European Tour Docs -- getting home for X-rays! Back 9 painful to play -- hit a root coming down on #9 & snapped my elbow!" the 45-year-old wrote.
Scotland's Peter Whiteford, ranked 236th in the world, led by two shots at the halfway stage after carding 68 on Friday.