Open champion regards his final round of 66 at Muirfield on Sunday as "the round of my life" after the American overcame a five-shot deficit to win the Claret Jug by three strokes.
Open champion: Phil Mickelson
The southpaw's five-under par round was the lowest of the week and saw him finish three shots ahead of Sweden's Henrik Stenson, with English pair Ian Poulter and Lee Westwood four back.
"This is such an accomplishment because I never knew if I'd be able to develop my game to play links golf," the now five-time major winner said after his triumph.
"I never knew whether I would be equipped, have the shots, have the opportunity to do this."
The 43-year-old came into contention for the title after he went out in 34, but was pegged back after making bogey at 10.
However, he then played the best back nine of the week when he came back in 32, with birdies at 13, 14, 17 and 18 handing him the club-house lead and eventually the title.
The victory also moved Mickelson up to second on the world rankings, the highest he has been since September 2010.
"We had such firm, fast conditions here, the epitome of links golf, to putt better than I've ever putted, to shoot the round of my life feels amazing," Mickelson - who first moved into the lead with two holes left in his round - continued.
"When I made that putt on the 13th to get back to level par I thought that would be a score that was going to contend and have a great opportunity to win - and I made some great putts coming in.
"I knew that it was so difficult coming down the stretch that having to make birdies to chase somebody down would be extremely difficult.
"You have to be resilient in this game, you have to accept losses and use it as motivation to work harder and come back strong rather than letting it defeat you."
Butch Harmon, Mickelson's coach, echoed his statements, saying his performance around the tricky Muirfield course was as "the best round of golf I've seen".
"I said when Greg Norman won in 1993 that that was the best round of golf I've seen, but I think this one tops it," said Harmon, who has coached four different players to Open victories.
"Today the wind blew harder than it has and to go around when you knew you had to do it is absolutely brilliant.
"It took him a long time to understand how to play links golf. Phil plays very aggressive, but you can't do that with links golf. He just embraced how to play on links."
golf365.com