Zach Johnson survived a two stroke penalty on the final hole to win the Crowne Plaza Invitational at Colonial by one stroke from Jason Dufner.
Johnson had thought his winning margin was three strokes but he was penalised two of those for failing to replace his ball in the right place before making his final putt at the 72nd hole of the tournament.
After being informed of his rule violation Johnson took full responsibility and said of the mistake which cost him a double bogey: "I'm sure I'll get grief about it back home."
Dufner had been bidding to become the first player to win the two North Texas tournaments in back-to-back weeks, having claimed the HP Byron Nelson Championship a week ago.
He admitted: "I didn't have it today."
Dufner struggled off the tee all day and shot a four over 74 as Johnson carded a 72 which left him on 12 under, one stroke clear.
The consolation for Dufner was that he remained leader in the FedEx Cup standings while Johnson has moved up to third.
Dufner started the day one shot ahead of Johnson, and eight shots clear of the rest of the field.
During a tense final round there were four two shot swings as the lead exchanged hands several times.
They were tied at 14 under after 13 holes but Johnson birdied the next to lead.
Dufner saw his approach to the 15th roll into water and he suffered a triple bogey.
With both players making par on the final hole it looked like Johnson had won by three shots.
But Johnson had moved his ball out of Dufner's line and failed to move it back, meaning he played his ball from the wrong spot.
The penalty cost him two strokes but he still had a one shot lead and took the title.
Spain’s Sergio Garcia was the leading European Tour Member after a 68 left him tied for 13th on two under, one ahead of Louis Oosthuizen (73).