-13 J Furyk* (US), B Davis (Eng) -10 B Van Pelt (US), Luke Donald (Eng) -9 K Blanks (US), C Villegas (Col), R Barnes (US), Selected others: -5 P Casey (Eng), R Karlsson (Swe), F Jacobsen (Swe) * Furyk won at first play-off hole
Davis was trailing by one shot going into the final round.
Jim Furyk won the Verizon Heritage in bizarre circumstances after Londoner Brian Davis suffered a two-shot penalty at the first play-off hole.
Davis birdied the last hole at Hilton Head Island for a 68 to finish level with the American on 13 under par.
But at the first play-off hole, the Englishman told officials his club struck a reed, incurring a penalty.
Furyk holed out for a par to clinch victory, with Luke Donald in a tie for third with Bo Van Pelt on 10 under.
Seeking his first victory on the PGA Tour, the 35-year-old Davis sunk an 18-foot putt on the 18th to set-up the play-off with Furyk.
If I had thought I hadn't (committed an infraction) then I wouldn't have called it
But the same hole proved his undoing as he sent his approach on the first sudden-death hole into sand amongst rocks on the beach.
Davis chipped onto the green but immediately called over a rules official because he believed his club might have made contact with a loose impediment.
The officials consulted a TV replay and deemed that Davis had struck the reed on his backswing which incurred a two-shot penalty. With Furyk on the green, it effectively ended the contest.
"If I had thought I hadn't (committed an infraction) then I wouldn't have called it," said Davis.
"I knew about the rule. When we looked at it, I didn't think it was an issue. I thought the hole would be over the top of it.
"And obviously when I took the club away, I took it lower and obviously just grazed the thing.
Awkward for him to lose that way, and a little awkward for me to win
"It's one of those things where there's a bunch where the weeds were piled up together, and it's stuck in the ground, but it's not fixed, it's a loose impediment. So it's classified as sand, it's not actually fixed in the swing, and he (PGA rules chief Slugger White) said it was a two-shot penalty, and that's that."
Furyk, who shot a last-round 69, putted out for his 15th PGA Tour win and second since March, earning him $1.026m. He also climbed one place to fifth in the world rankings.
"To have the tournament come down that way is definitely not the way I want to win the golf tournament," Furyk said. "It's obviously a tough loss for him, and I respect and admire what he did.
"To be there and be in the battle and have an opportunity to win, and then have to call a penalty on yourself has got to be extremely disappointing.
"It's a testament to our game and the people that play on the Tour, and that we have so many guys that do that.
"It's just awkward to see it happen at such a key moment. Awkward for him to lose that way, and a little awkward for me to win."
White, the PGA Tour tournament director and rules official, also credited Davis for his honesty.
"That will come back to him in spades, tenfold," White said.
"In fact, on the putting green, after it was all said and done, I don't know if Jim said, 'are you sure?' but he said, 'I know I did. I could not have lived with myself if I had not called it on myself'. He's class, first class."
Davis, the world number 170 going into the tournament, was frustrated by dropping shots on the 15th and 16th and missing a birdie putt on 17.
"I've got to learn from that and make a couple of putts on the back nine, that's what makes a champion," said Davis, who has now had four runner-up finishes in the last four years on the PGA Tour.
"It then came down do 18, and I made an unbelievable second shot and obviously I made the putt. It was great getting in the play-off, but it was a disappointment (not to win)."