Phil Mickelson maintained a one-shot lead after two rounds of the US PGA Tour's Northern Trust Open, buoyed by a dramatic eagle from the fairway that helped offset some less impressive play. "I probably didn't play the greatest today, but I was able to kind of salvage a good round," said Mickelson, who carded a one-under par 70 at Riviera Country Club for a six-under total of 136. He was one shot in front of Pat Perez, whose six-under 65 matched the best round of the day and gave him sole possession of second place on five-under 137. Australian Jarrod Lyle also carded a bogey-free 65 to lead a group sharing third place on four-under 138. A handful of players failed to finish before darkness fell, but none figured on the leaderboard. Mickelson, seeking to earn a second straight US tour title after a scintillating come-from-behind victory at Pebble Beach on Sunday, took a one-shot lead into the second round. He struggled to build momentum, but got a big break at the 460-yard par-four eighth -- his penultimate hole -- where his L-wedge from 110 yards out found the hole. Mickelson said he wasn't firing at the pin, but trying to "sidespin" the ball towards the hole. "It kind of sidespun right in the hole, so it worked out just perfect," he said. Not everything in the four-time major winner's day turned out so well, but he still headed into the weekend in prime position to add a third title at Riviera to those he claimed in 2008 and 2009. "I made some good par putts today," said Mickelson, who was in two bunkers at his opening hole, the 10th, and saved par with a 14-foot putt. He was in a greenside bunker at the third, his 12th hole of the day, but made a nine-footer to walk off with a par. He closed his round with the last of his three bogeys of the day, missing a six-footer to save par at the par-four ninth. Mickelson's lapses saw Sweden's Carl Pettersson briefly take the second-round lead, before settling for a one-under 70 that left him the group alongside Lyle on 138 that also included Jimmy Walker (66) Matt Kuchar (69) and Jonathan Byrd (70). Lyle birdied all three of Riviera's par-fives. He was four-under on the front nine and picked up two more of his six birdies coming in. He kept his card blemish-free despite a poor chip at the last that left him a tricky eight-footer for par. "Any time you can shoot bogey-free around any golf course it's pretty good," Lyle said. "But this is a golf course that is very, very easy to make bogeys on. "Today was good. I didn't get myself in any trouble and actually holed some putts, which was nice." Perez said he felt a little off physically at the start of the day, but after his six birdies the 35-year-old was feeling much better. "I hit some pretty good shots," said Perez, whose lone US PGA Tour win was at the 2009 Bob Hope Classic. "Didn't hit it great, I just putted pretty well." Perez capped his round with a rare birdie at the par-four 18th, where he hit his second shot from the rough to 12 feet and made the putt. World number one Luke Donald, playing his first US event of the season, carded a one-over 72 for an even-par total of 142. Defending champion Aaron Baddeley was also at even par through 36 holes, a group that Joe Ogilvie joined with help from a hole-in-one with a seven-iron at the 166-yard par-three 16th.