Purdy, one behind Byrd, hit a spectacular approach to the 18th hole at En-Joie Golf Club that stopped 5 feet from the hole. Byrd played his second 20 feet short of the hole and figured he would have to make that to win the tournament outright.
Byrd gave his birdie try and good roll and burned the edge of the cup. He tapped in for par then watched the unbelievable happen. Purdy pulled the short birdie putt, giving Byrd the win.
'This feels great,' said Byrd, who pocketed $540,000 for the win. 'I thought I poured that one right in the center. Ted played so good today. I thought for sure he would make that one.'
Byrd earned his first title of 2004 and his second on tour. He captured the 2002 Buick Challenge, but this win is significant since he underwent hip surgery in February.
'This has been a long year for me,' said Byrd. 'Everybody has helped me to get me where I am -- back. Today is a stepping stone for me.'
Purdy also carded a 68 on Sunday and was dealt his second blow of disappointment this season. He took the lead into Sunday's final round at the Heritage, but lost in a five-hole playoff.
Todd Fischer (65), Robin Freeman, Hidemichi Tanaka (65) and Notah Begay III (69) shared third place at 18-under-par 270.
Heavy rain forced play to be suspended for over six hours on Sunday. As Purdy missed his birdie putt, it had gotten quite dark at En-Joie and there would have been the chance of a Monday playoff finish.
But the tournament was completed in regulation, although a playoff looked certain during the round. At one point on the back nine, eight players were tied for the lead at 18 under par.
Byrd ran home a 3-foot birdie putt at the 11th to go to 19 under and take a one-shot lead. He ran into trouble at the par-5 12th. He missed the green short and right and Byrd did his best to carry a greenside bunker, leaving his shot on the fringe. Byrd bogeyed the hole, tying him atop the leaderboard with Begay, Purdy, Fischer, Tanaka, Freeman, Robert Gamez and Camilo Villegas.
Byrd was the first to break out of the logjam. At the 15th, Byrd rolled home a 15-foot birdie putt to get to 19 under par, which was good for a one-stroke lead. He tallied another birdie at the 16th to go two ahead, but Purdy was not done.
Purdy sank a 12-foot birdie putt at the 17th to close the gap to one. Byrd missed the green, but was able to save par and keep his one-shot lead with one to play.
When the putt did not fall, Purdy held his head in his hands in disbelief and Byrd walked over the shake his hand.
'I played the par-5s even par today, which is just sinful for me,' said Byrd. 'I hit a great shot at 15 and 16 was an awesome up-and-down. Just keep trying to get better.'
Villegas carded a 3-under 69 and tied for seventh place with Vaughn Taylor (66) and Neal Lancaster (68). That trio came in at 17-under-par 271.
Gamez bogeyed 15 and 17 en route to a 1-under 71. He shared 10th place with Neal Lancaster and Jim Gallagher, Jr., who posted matching rounds of 4-under 68. They finished at minus-16.
Craig Stadler, the winner in 2003, shot a 4-under 68 on Sunday and he tied for 21st place at 13-under-par 275. His son Kevin, a two-time winner on the Nationwide Tour, only managed an even-par 72 in the final round and was part of a group in 40th at minus-10.