But by the end of one of golf's longest days, Mickelson had finally exorcised Tiger from his psyche.
The pay-per-view audience likely will remember this match-play marathon mostly for lasting 22 holes and finishing on a 93-yard sudden-death hole that the two played not once, not twice, but three times. Mickelson ended the proceedings by sinking a seven-figure putt from four feet, while Tiger missed his last chance from eight feet.
But Mickelson's actions on the 21st hole provided a lasting memory.
Mickelson had Tiger between the crosshairs, having made his par putt while Woods needed to hit a six-footer to maintain the tie. On any other day, a six-footer would have been a gimme for Tiger, but on Friday, he was undependable from 10 feet in. He missed a par putt from three feet on No. 2, and the misses from close range kept on coming.
Mickelson also endured his share of shaky moments early on, starting with a missed nine-foot birdie putt on the first hole. That cost him a $200,000 side bet for failing to deliver his promised opening birdie.
"It didn't break, damn it," he muttered softly.
But that was as much outward emotion as he'd display all day, even during a match in which neither player ever led by more than one hole.
On the 21st hole, Lefty didn't bother seeing whether Tiger would fold from close range again. Instead, he took his foot off the gas and conceded the putt.
"I don't want to win like this," a mic'd-up Mickelson announced as he conceded Woods' putt.
With $9 million at stake, anyone else on the planet would have kept his mouth shut. But Mickelson backed off, and it's easy to understand why.
After being the perennial silver medalist to the greatest golfer of this century, Lefty wanted to do it right. He wanted to win like a champion rather than cash the big check because of a Tiger stumble.
Thus, they went back to the tee box one more time. From there, Mickelson launched the near-perfect shot that allowed him to purge the haunting specter of Tiger from between his ears.
"To be able to have just a little bit of smack talk for the coming years means a lot to me," Mickelson said afterward. "My heart can't take much more."
The biggest test of Mickelson's vital signs came on the the par-three 17th, when Woods landed just off the green and Phil had a short putt for birdie that was seemingly about to put him 2-up and clinch the match. But Woods chipped in from about 20 feet, and it felt like the momentum was suddenly on his side.
"Just like old times, brother," Tiger told his caddie.
Whether Mickelson heard that comment is irrelevant, because he undoubtedly felt it. Same old Tiger. Same old walls closing in as the man with 14 major titles roars down the homestretch.
But Mickelson owned the moment.
"You've been doing that crap to me for 20 years," he said matter-of-factly. "I don't know why I'm surprised now."
His nerves were frayed at that moment. A $9 million purse tends to do that.
Mickelson admitted as much to Tiger earlier, when he addressed his failure to deliver the trash talk and needling that he promised during promotions for The Match.
"I'm trying to be more talkative, but I just can't," Mickelson said to Woods as they headed for the 15th green.
But this match wasn't going to be won by strategic chit-chat. It was a test of survival on a day when two all-time greats struggled under the weight of having $9 million on their shoulders. Even with the course shortened and the pins placed ideally for low scoring, they both had trouble finding the bottom of the cup.
Lefty's win at the age of 48 doesn't compare to Jack Nicklaus winning the Masters at 46, and the quality of the showdown certainly doesn't rank with the Ali-Frazier or Brady-Manning battles. But Mickelson has been looking for this victory for his entire career, as he's never won a major while Tiger finished second.
Although it didn't include as much smack talk as Mickelson promised, there will be plenty of time for that down the road.