Phil Mickelson, tuning up for a run at a fourth Masters title, had seven birdies but settled for a share of second place behind Andrew Putnam after two rounds of the Houston Open.
Putnam nabbed six of his seven birdies in his last seven holes, his seven-under 65 vaulting him to the top of the leaderboard on 12-under-par 132.
Mickelson's seven birdies were balanced by two bogeys in a five-under-par 67 that left him tied for second on 133.
He was joined on 11 under by unheralded American Austin Cook, who birdied his last four holes in a seven-under 65.
It was a further stroke back to Canada's Graham DeLaet, who carded a 67, and American Luke Guthrie, who signed for a 68 for 134.
Putnam, a PGA Tour rookie with just one top-25 finish on his resume, teed off on 10 at the Golf Club of Houston and was one under through nine holes.
But he caught fire coming in, stringing together four straight birdies starting at the par-four third.
He punctuated his round with two more birdies at eight and nine -- from the rough at the par-five eighth and with a 15-foot putt at the final hole.
Mickelson had set the early pace.
After going birdie-bogey at the second and third holes, Mickelson added three more birdies on the front nine.
His march continued with birdies at 11, 13 and 15 -- where he rolled in a 22-foot putt.
Mickelson's lead dwindled as a wayward tee shot cost him a bogey at 17, but he regrouped for a solid par at the last and held the clubhouse lead before Putnam stormed home.
Mickelson, who has yet to post a top-10 finish this season, is looking for a boost heading into the first major of the year at Augusta National next week.
He'll have plenty of competition on the weekend. Rising star Jordan Spieth carded a 66 on Friday and headlined a group of six players sharing sixth place on nine-under 135. He was joined by fellow American's Shawn Stefani, J.B. Holmes, Hunter Mahan and Mark Wilson and France's Victor Dubuisson.
Source: AFP