Stadler trailed by eight strokes during round three. However a double-eagle two on the par-5 16th Saturday, turned his fate around.
'I was never in this golf tournament until a hole and a half to go,' said Stadler, who picked up $345,00 for the win. 'I guess it was fairly surprising at the end. You look at the board all through the day and it didn't look like I was in it.'
Jerry Pate at one point owned the lead late in the round, but closed bogey-bogey to end in second place at 12-under-par 276 after a round of 6-under 66. He was joined there by Allen Doyle, who carded a final-round 1-under 71.
Overnight co-leaders Peter Jacobsen and Vicente Fernandez struggled to final round 73s to finish two shots back at minus-11. They were joined there by Andy Bean, Bruce Fleisher, D.A. Weibring, Tom Kite and Doug Tewell.
Stadler, the 2003 Ford Senior Players Championship winner, opened with birdies at the first and third to move to 10 under. However, he fell off the pace as he bogeyed Nos. 4 and 8, both par-4s.
The Walrus caught fire on the back nine. He birdied the 10th and the 12th, both par-4s, to return to minus-10. After the second of his two back nine pars, Stadler tripped to a bogey at the par-3 14th.
Stadler turned it up a notch from there. He birdied the par-5 15th and came right back to birdie the next to get to 11 under on the South Course at The Reserve Vineyards & Golf Club.
The 51-year-old converted his third straight birdie at the 17th to forge a four-way tie for the lead at minus-12. Stadler, a six-time winner on the Champions Tour, got up-and-down for birdie at the last to take the lead with four players left on the course.
'I'm still shocked I won this week,' Stadler said. 'I didn't really putt well all week, but I made some coming in today. I hit a good shot on 17, made birdie and never dreamed Pate would bogey 17 and 18. I got up to the 18th green and saw the leaderboard with the bogeys and said, 'you know they keep opening the door a little bit and somebody's going to stick their foot in there and fortunately it was me.''
Pate roared up the leaderboard as he played his first 15 holes in 6 under par to jump to minus-12. He then holed out from the fairway at the par-5 16th for eagle to move to 14 under.
Owning a one-stroke lead, Pate stumbled in with back-to-back bogeys. He was aiming for his first win since the 1982 Tournament Players Championship on the PGA Tour.
Doyle played his first nine holes at even-par with one birdie and one bogey. Around the turn, he parred the first six holes of the back nine. He then moved to 12 under with a birdie at the 16th. However, he could only manage pars at the last two holes to end there.
Jacobsen, the hometown favorite, never got anything going on Sunday. He bogeyed the first and fell three behind Fernandez, who birdied the same hole. Jacobsen got back to 12 under with a birdie at the 12th.
Standing in a logjam top the leaderboard, Jacobsen's tee shot at the 17th came to rest inside a hazard line, but on grass. Standing in the water hazard, Jacobsen tried to play his second from a tough stance. He barely got his club on the ball and it splashed into the water.
Jacobsen, who donated his earning back to JELD-WEN for their commitment to the event, eventually left the 17th with a double bogey. He birdie the last to join the crowd in fourth place.
'I hit six or seven putts today that looked like they were going in, but didn't,' said Jacobsen, who said it would be a dream come true to win this event.
Fernandez owned the lead most of the final round thanks to his birdie at the first. He battled to 14 straight pars to remain atop the leaderboard. The Argentine fought a balky driver down the stretch.
At the 16th, Fernandez lost his drive in the left rough and struggle to a bogey. His drive at 17 flared right and led to another bogey that dropped him to 11 under. Needing an eagle at the last to force a playoff, Fernandez could only par the hole to finish two shots back.