Dead, solid silence.
It's not that Haas is an unpopular golfer. It's just that Haas' beautiful birdie denied Phil Mickelson a second consecutive tournament victory.
Haas beat both Mickelson, who a week earlier had shot a closing-round 64 to win the AT&T Pebble Beach National Pro-Am, and Keegan Bradley in the playoff, and the crowd reacted as a group of 5-year-olds might when told that Santa Claus didn't exist.
"I like it when the crowd cheers," said Haas, who won $1,188,000 with the victory. "Honestly, 'Phil' sounds really similar to 'Bill,' so you just kind of pretend that maybe they're for you."
Haas, 29, had finished regulation at seven under par after his round of two-under 69 Sunday and went to the driving range. He had a one-shot lead when Mickelson, Bradley and Bryce Molder, playing in the final group, headed to the 18th, where only six golfers had recorded birdies in the tournament.
That number became eight when first Mickelson, from about 25 feet, and then Bradley, from 12 feet, made a three on the 475-yard, par-four finishing hole, causing an uproar.
Mickelson, shot 71 Sunday, shouted, pounded his putter into the ground and bumped fists with Bradley, telling the 25-year-old, "Join me."
"It felt great," Mickelson said. "I let out some emotion because it had been going on for so long."
Indeed, on the par-five 17th hole, Mickelson's 21-foot birdie attempt rolled to within an inch of the cup, close enough to make Mickelson stop and stare for a moment, hoping the ball might drop in.
"It sure was right in the middle," Mickelson said. "It just needed a little bit more roll."
Mickelson, Bradley and Haas replayed No. 18 as the first playoff hole, and all made par. Next they went to the 10th hole, and if momentum mattered, if the will of the people mattered, Mickelson would have left Riviera with the 41st title of his career.
But although Haas won the tournament with that final playoff putt, Mickelson might have lost it earlier with his only two three-putt holes of the week, resulting in consecutive bogeys at the par-three 14th and par-four 15th.
"I was very tentative on the greens today," Mickelson said. "I wasn't trying to be. I was trying to knock them in, but [the greens] just weren't as fast as I was perceiving them to be."
Haas, playing two groups ahead of Mickelson and Bradley, steadied himself after consecutive bogeys at Nos. 12 and 13 had seemed to knock him out of contention.
"I was just somewhat under the radar," Haas said. "That's fine, flying under the radar. And you've got to fight your inner demons and not get down. I just hung as tough as I could and it all worked out."
It seemed as if it might work out for Mickelson after the dramatic final hole of regulation.
Bradley, the 25-year-old who won his first major title, the PGA Championship, last year, said he expected Mickelson's birdie putt to be good.
"I knew Phil was going to make that putt," Bradley said. "I was honestly ready for him to make it. I knew having to putt second would be difficult because the crowd is so behind him.
"But credit to the crowd. They really quieted down for me."
Bradley, however, said he didn't expect the same dramatic make from Haas in the playoff.
"I didn't think he was going to make that one," Bradley said. "I should have known, though. He's a great putter."