Five strokes ahead of the field overnight with compatriot Ricky Barnes, Glover closed with a three-over-par 73 at a blustery and overcast Bethpage Black to triumph by two shots.

The 29-year-old, whose only previous PGA Tour victory came at the 2005 Disney Classic, kept his composure in nerve-jangling conditions to post a four-under total of 276.

"It was a test of patience today," a beaming Glover said after earning the winner's cheque for $1.35 million. "It was tough. The golf course played fantastic but it was just hard today.

"I was pretty nervous coming down the stretch and 16 obviously was huge," he added, referring to a six-foot putt there for his only birdie of the day. "I hit the shots today that I had to hit in the situation."

Tour rookie Barnes, like Glover a qualifier, slid out of contention with five bogeys in seven holes from the fifth on the way to a 76 and a tie for second place.

Also at two under were three-times major winner and crowd favorite Mickelson, who carded a topsy-turvy 70, and former world number one Duval, after a five-birdie 71.

"I put myself in a great position to close it out but unfortunately I didn't finish it off," Mickelson said after claiming a record fifth runner-up spot at the US Open.

"Certainly I'm disappointed but, now that it's over, I've got more important things going on."

Mickelson's wife Amy, diagnosed with breast cancer last month, is scheduled to start treatment on July 1.

Britain's Ross Fisher eagled the par-five 13th to close to within a stroke of the lead before bogeying two of the last four holes for a 72 and fifth place at one under.

BIRDIE OPPORTUNITIES

Triple champion and holder Tiger Woods, who failed to make the most of his birdie opportunities all week, closed with a one-under-par 69 to tie for sixth at level-par 280.

Mother Nature finally stepped aside after a rain-soaked week of lengthy delays at Bethpage to allow the golf to dominate as the year's second major came alive on the back nine.

Left-hander Mickelson spectacularly eagled the 13th to move into a tie for the lead with Glover at four under, striking a superb second shot to four feet and coolly knocking in the putt before pumping his left fist in celebration.

His challenge faded, however, when he bogeyed 15 and the par-three 17th where his tee shot ended up in rough just short of the green.

Duval, bidding for his first title anywhere in the world since 2001, joined Glover atop the leaderboard with three consecutive birdies from the 14th.

He rammed in an eight-footer on 16 to get to three under before slipping back with a bogey at the tricky 17th where he horse-shoed out from four feet with his par attempt.

Glover, who held a slender one-shot cushion with three holes to play, stumbled at the par-four 15th after finding the first cut of rough on the right and three-putting for bogey.

However, the world number 71 immediately recovered with his only birdie of the day at the 16th, rolling in a six-footer to regain the outright lead at four under.