Augusta, Ga. ? Phil Mickelson in a green jacket. Even he had a hard time believing it.

The final leg in his odyssey to win a major championship came down to an 18-foot putt Sunday, the kind Mickelson had grown weary of watching others make as he stood to the side.

This time, the last chance belonged to him, a birdie putt that kept him in suspense to the very end. It rolled toward the cup, swirled around the left edge and dropped in.

Mickelson leapt as high as he could and threw both arms in the air, kissed the ball that he plucked from the cup and tossed it into a delirious crowd that felt the same way.

“It almost feels like make-believe,” Mickelson said. “My first thought was, ‘I did it! I finally did it!’ I knew I could, but I finally did it.”

Those who doubted only had to look at his poise along a dramatic back nine at Augusta National as Ernie Els tried to pull away with an eagle, a birdie and a collection of clutch pars.

Mickelson birdied five of the last seven holes and shot 31 on the back — the best finish by a Masters champion since Jack Nicklaus had a 30 in 1986. He closed with a 69.

The best proof of all was a 43-long green jacket.

“I can’t believe this is happening,” Mickelson said after Mike Weir slipped the jacket over his shoulders.

Phil Mickelson celebrates after winning the Masters with a birdie on the 18th hole. Mickelson won his first major championship -- in his 43rd attempt -- Sunday at Augusta, Ga.

It sure beat the other thing he’s been carrying on his back for 12 years.

“This is the fulfillment of dreams,” he said. “I’m just proud to be a champion here. It was an exceptional, unbelievable back nine, and it’s something I’ll remember forever and ever.”

Even as he sat in fabled Butler Cabin, he was reliving the 15-foot birdie putt on the par-3 16th that gave him a share of the lead, and an 18-footer on the final hole that made Mickelson only the fourth player in Masters history to win with a birdie on the final stroke of the tournament.

Until Sunday, he was known as the best player to have never won a major.

Now, he’s simply one of the best in the game.

“I didn’t think there was any way he would miss it,” said Chris DiMarco, who played in the final group and had a par putt from exactly the same line that allowed Mickelson to get a good read.

Els felt helpless after closing with a 67. He was rapping putts on the practice green, hopeful of a playoff and a chance for the third leg of the Grand Slam, but was jolted into despair at the sound of the cheer.

“I played as good as I could,” Els said.

Masters champion Phil Mickelson hugs 2003 winner Mike Weir after being presented with his green jacket. Mickelson finished at nine-under Sunday at Augusta National.

Mickelson knows that feeling all too well. Of the half-dozen close calls he has had in the majors, nothing was more jarring than Payne Stewart holing a 15-foot par putt on the final hole at Pinehurst to win the 1999 U.S. Open, or David Toms making par from 12 feet at the 2001 PGA Championship to beat Mickelson by one shot.

“I think Phil deserved this one,” Els said.

Before walking into the scoring hut to sign his card, Mickelson grabbed daughter Amanda and said, “Daddy won. Can you believe it?”

Mickelson finished at 9-under 279 and earned $1.17 million for his 23rd career victory.

This was the sixth straight major won by a first-timer — something that had never happened in 144 years of championship golf.

K.J. Choi holed a 5-iron from 220 yards on the 11th hole for eagle, kept his hopes alive with a 40-foot birdie putt on the 13th but wound up with a 69, three shots behind.

Tiger Woods was long gone before the fireworks started. He made a double bogey — his third of the tournament — on the 13th hole and shot 71, leaving him 11 shots out of the lead in a tie for 22nd, his worst finish ever at the Masters.

Woods now has gone seven majors without winning, and he has played his last five over par.

But this Masters didn’t need him to deliver the drama.

With aces and eagles, so many spectacular shots along the back nine that the gallery was out of breath, it came down to Mickelson and Els in a duel as good as any at a major championship.

Els, playing two groups ahead of Mickelson, beat him on the par 5s with an eagle and a birdie.

Mickelson answered with an approach to the dangerous 14th that grazed the cup for a tap-in birdie, and a 15-foot birdie on the par-3 16th, a hole that has haunted him in the past.

“Baby!” Mickelson said as he trotted off the green, tied for the lead with two holes to play.

Playing the final hole, Els hit into a bunker so deep he could only see the hazy sky. He blasted out and said, “Be right!” and it stopped some 25 feet behind the cup. His birdie putt turned just left of the hole.

Mickelson had never come to the final hole in a major with a share of the lead.

He never faced a more important putt in his life. He never showed so much raw emotion when it was over.

“I was watching myself look like an idiot on the 18th green after I made the putt and really didn’t care,” he said. “It was just so much fun.”

Only two other players — Harry “Lighthorse” Cooper (31) and MacDonald Smith (24) — had more PGA Tour victories than Mickelson’s 22 without winning a major.

Some began to doubt it would ever happen, especially since Mickelson was coming off his worst season ever. A year ago, he nearly lost his wife, Amy, during a difficult birth of their first son.

He refused to start practicing until Jan. 1, determined to put last year behind him. Now, Mickelson can look forward to many more tries at majors, without the pressure of having to win his first.

“Get used to me, because I’m going to be back every year,” he told Augusta National members.