He wound up holing a 45-foot birdie putt across the green to win the Northern Trust Open.
"A part of me was saying, 'I've done this once, let's do it again,' " Haas said. "Another part of me was saying, 'Don't screw this up.' "
Mickelson and Bradley worked their own heroics just to get into the playoff.
Haas, who closed with a 2-under 69, was on the practice range at 7-under 277 as he warmed up for a playoff only he thought might happen. He was trying to convince himself that Mickelson or Bradley - maybe both - would make birdie on the 18th hole, even though it had yielded only six birdies all day.
With tournament executive director Jerry West - "Mr. Clutch" from his days with the Los Angeles Lakers - looking on, Mickelson rammed in a birdie putt from just outside 25 feet, pointing his putter and slamming his fist as the gallery packed into the hill below the stately clubhouse let out a cheer that could be heard down Sunset Boulevard.
Mickelson bumped fists with Bradley and told his protege, "Join me."
That he did. Bradley's birdie putt from just outside 12 feet took one last, slow turn at the cup and disappeared, setting off another enormous cheer. No one had to tell Haas what was happening.
"You heard the cheers," he said.
In other tournaments *
At Naples, Fla., Kenny Perry shot a 2-under 70 for his second Champions Tour title, cruising to a five-shot victory in the ACE Group Classic. Perry, who finished at 20-under 196, totaled 24 birdies - two short of the tour record for a 54-hole event - and tied Allen Doyle (1999) for the largest margin of victory in the 25-year-old tournament.
Defending champion Bernhard Langer shot a final-round 70 to finished second at 15-under 201.
* At Chonburi, Thailand, Top-ranked Yani Tseng shot a 6-under 66 to finish at 19-under 269 and successfully defended her LPGA Thailand title.
* At New Delhi, South Africa's Jbe Kruger won the Avantha Masters for his first European Tour title, shooting a 3-under 69 for a two-shot victory at 14-under 274.