One of the greatest final rounds in a major. Two of the best shots he ever struck with a 3-wood. The third leg of the Grand Slam.

Phil Mickelson never imagined any of this happening at the British Open.

No wonder he never took his hand off the base of that silver claret jug as he talked about the best Sunday he ever had at a major. Five shots out of the lead, Mickelson blew past Tiger Woods, caught up to Lee Westwood and Masters champion Adam Scott, and won golf's oldest championship with the lowest final round in his 80 majors.

With four birdies over the last six holes, Mickelson closed with a 5-under 66 for a three-shot win over Henrik Stenson.

No longer is he mystified by links golf, and he has his name etched in that jug to prove it.

``This is such an accomplishment for me because I just never knew if I'd be able to develop the game to play links golf effectively,'' Mickelson said. ``To play the best round arguably of my career, to putt better than I've ever putted, to shoot the round of my life ... it feels amazing to win the claret jug.''

Introduced as the ``champion golfer of the year,'' he held the oldest trophy in golf over his head to show it off to one side of the massive grandstand lining the 18th green at Muirfield, and then the other. An hour earlier, they gave the 43-year-old Mickelson the loudest ovation of the week as he walked up the final fairway.

He drained an 8-foot birdie putt and thrust his arms in the air, hugged caddie Jim ``Bones'' Mackay and whispered to him, ``I did it.'' After signing for the lowest final round ever at Muirfield, Mickelson huddled with his wife and three children _ back from a quick holiday to Spain _ for a long embrace and waited for the others to finish.

Westwood, who started the day with a two-shot lead, fell behind for the first time all day with a bogey on the par-3 13th hole and never recovered, closing with a 75.

Scott took the outright lead with a 4-foot birdie on the 11th, and then closed as sloppily as he did last year when he threw away the Open at Royal Lytham & St. Annes. He made four straight bogeys starting at the 13th, and a final bogey on the 18th gave him a 72. At least he has a green jacket from the Master to console him.

Woods, in his best position to win a major since the crisis in his personal life, stumbled badly on his way to a 74 and was never a serious challenger.

``We know that he goes for broke, and if that's how he was feeling and pulling it off, he's got the ability to do that,'' Scott said about Mickelson. ``And he's gone and won an Open easily. So every credit to him.''

At the end of a rough-and-tumble week along the Firth of Forth, Mickelson was the only player under par at 3-under 283. In his four other majors _ three Masters and one PGA Championship _ he had never started the final round more than one shot behind.

``I don't care either way how I got this trophy _ I got it,'' Mickelson said. ``And it just so happened to be with one of the best rounds of my career, which is really the way I've played my entire career. I've always tried to go out and get it. I don't want anybody to hand it to me. I want to go out and get it. And today, I did.''

Westwood, whose only other 54-hole lead in a major ended with Mickelson winning the Masters, paid tribute to Lefty for what will go down as one of the great closing rounds in a major.

``When you birdie four of the last six of a round any day, that's good going,'' Westwood said. ``With a decent breeze blowing and some tough flags out there, it's obviously a pretty good experience. When you do it in a major championship, it's an even better experience.''

But this major? Phil Mickelson?

He had only contended twice in two decades at golf's oldest championship. One week after he won the Scottish Open in a playoff on the links-styled course of Castle Stuart, Mickelson was simply magical on the back nine of a brown, brittle Muirfield course that hasn't played this tough since 1966.

Tied for the lead, Mickelson smashed a 3-wood onto the green at the par-5 17th to about 25 feet for a two-putt birdie, and finished in style with a 10-foot birdie putt on the 18th to match the lowest score of this championship.

``Those two 3-woods were the two best shots of the week, to get it on that green,'' Mickelson said. ``As I was walking up to the green, that was when I realized that this is very much my championship in my control. And I was getting a little emotional. I had to kind of take a second to slow down my walk and try to regain composure.''

Mickelson figured a par on the 18th would be tough for anyone to catch him. When the ball dropped in the center of the cup, he raised both arms in the air to celebrate his fifth career major, tying him with the likes of Seve Ballesteros and Byron Nelson.

``Best round I've ever seen him play,'' said his caddie, Jim ``Bones'' Mackay.

His final surge was right about the time Westwood and Scott began to fold.

Scott, trying to join an exclusive list of players who have won a green jacket and a claret jug in the same year, made a remarkable recovery from the dunes right of the par-3 13th hole, only to miss the 7-foot par putt. He took three putts for bogeys on the next two holes _ from long range on the 14th, and from 20 feet on the 15th _ and found a bunker on the next.

Westwood started to lose his grip on the jug with bogeys on the seventh and eighth, and failing to birdie the downwind, par-5 ninth. Presented with birdie chances early on the back nine, his putting stroke began to look tentative.

Westwood and Scott tied for third with Ian Poulter, who played a four-hole stretch in 5-under around the turn and closed with a 67. At 1-over 285, he canceled a flight home in case of a playoff. Moments later, with Mickelson pulling away, the outcome was clear.

Jack Nicklaus said on Twitter, ``Phil's round was incredible. After his bad break on 16 and to then get up and down showed a lot of guts. And the two great shots at 17 ended the tournament.''

Making this even sweeter for Mickelson is that just one month ago he lost out on yet another chance to win the U.S. Open, the missing link of a career Grand Slam. Mickelson twice made bogey with wedge in his hand on the back nine at Merion and had his record sixth runner-up finish.

Woods, Nicklaus, Gary Player, Ben Hogan and Gene Sarazen are the only players to win all four professional majors. Mickelson figured it would be the British Open that would hold him back. Now he has the jug, and he never took his hand off it during his press conference.

``I think that if I'm able to win the U.S. Open and complete the career Grand Slam, I think that that's the sign of the complete, great player,'' Mickelson said. ``And I'm a leg away. And it's been a tough leg for me.''

For now, Mickelson takes his place among an elite list of winners at Muirfield, which is considered the fairest of the links on the British Open rotation. All but two of the Open champions at Muirfield are in the World Hall of Fame. Mickelson is the only winner who already has been inducted.

It was the 43rd win of his PGA Tour career. The guy who once couldn't win the big one now has five majors in the last nine years. This one returns him to No. 2 in the world ranking for the first time in nearly three years.

Woods, meanwhile, now has gone 17 majors without winning, and that pursuit of Nicklaus and his benchmark of 18 majors _ Woods is stuck on 14 _ doesn't look any closer. He three-putted twice in four holes at the start of the round and looked like just another contender on this Sunday.

He attributed his poor day to not getting the right pace on the greens, which he said were progressively slower.

``I felt like I was really playing well today, actually the whole week, `` said Woods, who has not broken 70 in the final round of his last seven majors.  ``I really hit so many good shots and really had control of my ball this week. As I said, it was just trying to get the speed, and I just didn't get it.''(AP)