McDowell shot a final round three-over 74 to finish level par – one ahead of Havret, two clear of Ernie Els and three clear of Tiger Woods and Phil Mickelson.

McDowell started the day three shots behind leader Dustin Johnson but was the outright leader playing the 4th after Johnson imploded on his way to a final round 82.

Almost everybody on the leaderboard appeared to struggle under the Sunday pressure of a major and McDowell held a one stroke lead playing the 18th despite carding four bogeys and no birdies after the 6th hole.

The 30-year old considered attacking the par-5 72nd hole with his second shot but wisely laid up with a nine-iron after Havret, ahead on the green, missed a birdie putt that would have tied him for the lead.

“I had 220 (yards to the) front edge and I was debating whether to have a go in two and when I saw Greg (Havret) miss his putt I completely bailed out of that idea.”

McDowell said it was extremely difficult to fend off Havret and the brutal Pebble Beach layout and win his first major and first event in the US.

“It’s so difficult to win a golf tournament let alone a major championship and I’m just so thrilled to get over the line.”

Havret, who drained a putt from 50 feet in England to qualify for the US Open, defied his world ranking of 381 to fire the best round among the final three groups – one-over par 72.

“It was my first US Open, I holed a 50-footer to qualify at Walton Heath and all of a sudden I’m playing Sunday with Tiger (Woods), it’s a bit of a way to that”, Havret said.

Johnson made a triple bogey at the 502-yard par-4 2nd after taking two swipes at his ball in rough just right of the green.

The 25-year-old, described earlier in the week by his caddy as a ‘flat-liner’ who doesn’t feel nerves, followed with a double bogey at the 3rd after he lost his tee shot well left in knee-deep rough and a bogey at the reachable par-4 4th after blocking a three wood over the cliff.

Woods couldn’t escape the volatility of the leaderboard himself and again wasted chances on the front nine and never threatened the lead.

“I made three mental mistakes today and it cost me the (US) Open”, Woods said after his round of 75.

Els was the man to beat early as he tied the lead at three-under after his third birdie for the day at the par-5 6th.

But the big South African will rue a double bogey on the par-4 10th and the heavily bunkered par-3 17th – a hole he played in five-over par for the tournament.

Mickelson rolled in a birdie from off the front of the first green and could have parred the back nine to get into a playoff with McDowell.

“When I made that putt on the first hole (I thought) this was going to be a great day and we saw that Dustin (Johnson) made a triple early, it was anybody’s ball game”, Mickelson said.

Robert Allenby and Stuart Appleby fired respective rounds of 74 and 70 and both finished in a tie for 29th.