Scottsdale - Phil Mickelson came tantalisingly close to golf's magic number of 59 on Thursday, a near-miss at his last hole leaving him with a 60 and a four-shot lead in the US PGA Tour Phoenix Open.
Mickelson's 25-foot birdie attempt at his final hole of the day - TPC Scottsdale's par-four ninth - curled around the rim of the cup but didn't drop.
"You don't have chances to shoot 59 often," he said. "To have that putt on line - I'm kind of mortified that it didn't go in."
Only five golfers have carded 59s on the US PGA Tour, most recently Australian Stuart Appleby in the 2010 Greenbrier Classic.
Paul Goydos also accomplished the feat in 2010 at the John Deere Classic. Al Geiberger (1977), Chip Beck (1991) and David Duval (1999) have also posted 59s on the US tour.
Japan's Ryo Ishikawa carded the lowest round on a major professional tour with a 12-under 58 to win the 2010 Crowns on the Japan Tour.
Bo Van Pelt had a 59 in the pro-am here on Wednesday, which doesn't go into the record books as an official tournament round.
Mickelson's 11-under 60 gave him a four-stroke lead over five players when darkness halted play in the first round with 33 players still on the course. None of those who were to return to complete the round on Friday morning were threatening the lead.
Ireland's Padraig Harrington and Americans Brandt Snedeker, Ryan Palmer, Ted Potter and Jeff Maggert were tied on 64.
South Korea's YE Yang and Belgian Nicolas Colsaerts were among nine players on six-under 65.
But the day belonged to Mickelson, who was coming off a tie for 51st at Torrey Pines last week and was equal 37th in his first start of the season at La Quinta, California, earlier in January.
Teeing off on 10, the four-time major champion opened with four straight birdies. He strung together four more from the par-three 16th through the par-four first.
He birdied the par-five third despite finding a fairway bunker and moved to 10-under with a birdie at the fourth.
He managed just one more birdie, however, making a seven-footer at the par-three seventh.
Mickelson matched his best career round. He posted the same score in the second round of the Phoenix Open en route to his second title here.
Among those chasing him, Harrington is playing the Phoenix Open for the first time.
"It's a nice score, obviously, seven-under par," the three-time major champion said. "It's a little bit behind Phil, but still a nice score in itself. I pretty much got the most out of the round for the first 15 holes, then had three chances the last three holes and didn't hole the putts."
The tournament was without Fijian veteran Vijay Singh who withdrew complaining of a bad back shortly before the first round - and a day after he admitted using a deer antler spray that contains a substance banned by the PGA Tour.
Singh, a two-time winner of the tournament Wednesday confirmed a Sports Illustrated report that he used the spray made by Sports with Alternatives to Steroids (SWATS), but said he didn't realize it contained banned anabolic agent IGF-1.
Leading first-round scores on Thursday in the US PGA Tour $6.2m Phoenix Open (USA unless noted, par-71. Round halted by darkness with 33 players to finish):
60 - Phil Mickelson
64 - Ryan Palmer, Brandt Snedeker, Padraig Harrington (IRL), Ted Potter, Jeff Maggert
65 - Matt Every, Nicolas Colsaerts (BEL), Bill Haas, YE Yang (KOR), Brian Gay, Justin Leonard, Hank Kuehne, Martin Flores, Nick Watney
66 - Kevin Chappell, Ken Duke, Brendon de Jonge (ZIM), Jeff Overton, Robert Garrigus, Angel Cabrera (ARG), Ryan Moore