Golf: Mickelson struggles early while Koepka charges at US Open

La Jolla (United States) - World number 10 Koepka grabbed the lead after a blazing back-nine start

Phil Mickelson stumbled with three bogeys in his first six holes on Thursday chasing a US Open win for a career Grand Slam while Brooks Koepka charged into the first-round lead at Torrey Pines.

A day after his 51st birthday, hometown hero and back-nine starter Mickelson struggled to find the fairway and made the turn on 2-over, six adrift of four-time major winner Koepka.

Mickelson became golf’s oldest major winner last month by taking the PGA Championship at Kiawah Island to capture his sixth career major title.

But the US Open is the crown that has eluded the 30th-ranked left-hander, who has settled for a record six runner-up showings.

Mickelson, who began on the back nine, lipped out for par from just inside 15 feet at the par-4 10th hole, needed a penalty drop at the par-5 13th then found deep rough for bogey and at 15 was in left rough on his first two shots to drop another shot.

He recovered by sinking a 10-foot birdie putt at the 17th but the rally halted when he missed another from just inside six feet at the par-5 18th.

Mickelson hopes to join career Grand Slam winners Tiger Woods, Jack Nicklaus, Ben Hogan, Gary Player and Gene Sarazen.

World number 10 Koepka, meanwhile, grabbed the lead after a blazing back-nine start.

Koepka, seeking his third US Open crown in five seasons, rolled in a 20-foot birdie putt at the 12th hole, holed a 42-foot bomb at the 17th.

Koepka closed his first nine by dropping his approaching inches from the cup at the par-5 18th and tapping in for birdie and a share of the lead at 3-under.

He seized the top spot alone with a nine-foot birdie putt at the par-5 second to reach 4-under, one stroke ahead of fellow Americans Xander Schauffele and Patrick Rodgers.

Sixth-ranked Schauffele, another local favorite playing alongside Mickelson, birdied 10, sandwiched birdies at 12 and 14 around a bogey, and tapped in for birdie at 18 after missing an eagle bid from just inside 10 feet.

Rodgers reached 3-under with a birdie putt from just outside 18 feet at the 12th.

Early morning fog rolled in off the Pacific Ocean to delay the start by 90 minutes as a field of 156, with Mickelson the eldest, tested the formidable 7,652-yard, par-71 layout.

Such late-starting stars as fifth-ranked defending champion Bryson DeChambeau, four-time major winner Rory McIlroy, world number one Dustin Johnson and third-ranked Jon Rahm could be racing the darkness to complete their rounds.

Mickelson has won three times at Torrey Pines in US PGA Tour events but all were before a 2001 course renovation, forcing him to spend much of the past two weeks re-learning the nuances of a course he once knew well.

Mickelson remains a popular bet at 50-1 odds after his historic triumph at Kiawah Island, raising concerns from some oddsmakers about major payouts if he manages another shock win.

Johnson, last year’s Masters champion, could be overtaken in the rankings if number two Justin Thomas or Spaniard Rahm win the US Open.

Johnson would need to finish worse than solo 17th if Thomas wins or worse than a two-way share of 18th if Rahm wins to be dethroned.