That emotional victory paid dividends Sunday, when Weir shot a 2-under 68 for a one-stroke victory over Australia's Mark Hensby in the Fry's Electronics Open.
'It maybe got me over the hump as far as confidence that when it really hits the fan, I can get it done,' Weir said.
Weir got it done on a warm, blustery day at Grayhawk Golf Club. Wind gusted up to 25 mph, turning the 7,125-yard Raptor Course into an adventure. Only 12 players broke par on Sunday, 22 fewer than Saturday, when calm conditions prevailed.
Weir finished at 14-under 266 for his eighth PGA TOUR victory, and first since the 2004 Nissan Open, a span of 87 starts.
'Definitely been tough not winning,' said Weir, who earned $900,000 to jump from 84th to 33rd on the money list at $1,986,053. 'You know, that's what we're all out here to do, and 3 1/2 years has been quite a long time.'
Weir secured his long-awaited victory with a 6-foot par putt after hitting his approach on the par-4 18th into a greenside bunker.
'It was gusting across there,' he said. 'It's pretty open on that green, and my pant legs were whipping pretty good there when I hit that putt. I just told myself to keep my head nice and steady and just try to hit it nice and solid.'
Fans serenaded a grinning Weir with a rendition of 'O Canada' after he spoke to reporters.
The 2003 Masters champion took the lead with a birdie on the par-4 15th, rolling a chip shot to a foot, then held off Hensby over the final three holes.
'I think the turning point probably in the tourney was 15,' Hensby said.
Hensby closed with a 69. He moved up to 99th on the money list, at $969,731, assuring himself of his tour card for next season.
Billy Mayfair, a Scottsdale resident and Arizona State product, shot a 68 to finish third at 10 under.
Carl Pettersson, who led after three rounds, and Sean O'Hair tied for fourth at 9 under. Pettersson shot a 74, and O'Hair had a 69.
O'Hair briefly shared the lead after birdieing the 16th. But he double-bogeyed the 17th and bogeyed No. 18 to drop out of contention.
Pettersson opened the day with a one-stroke lead over Hensby and Weir.
By the second hole, they were all tied for the lead. But Pettersson dropped another stroke on the par-3 fifth hole, and fell behind by bogeying the 10th, 11th and 12th.
Hensby and Weir dueled the rest of the way, with no more than a shot separating them over the entire round.
That's where Weir's confidence, inspired by his Presidents Cup victory over the world's No. 1 golfer, came to the forefront.
'All of those matches were pressure-packed during the Presidents Cup, and everything about my golf swing felt great,' he said. 'So I think maybe it did solidify it a little bit, but I've always believed in what I'm doing, that's for sure.'
Hensby missed a chance to pull even on the par-4 17th. Weir hit his second shot on a slope to the left of the green, but Hensby's second shot also sailed past the green. Both players chipped within a few feet to save par.
On 18, Hensby had a chance to force a playoff when Weir hit his second shot into a greenside bunker. But Hensby's chance died when his chip shot from an embankment missed by less than a foot and Weir chipped to about 6 feet, then rolled home the winner.
'I've been practicing a lot of little bunker shots and made a nice adjustment in the bunker and got the ball to come out nice and soft,' Weir said. 'You know, I could not have hit it much better than that.'