Playing in the final group with Watson and third-round leader Brian Harman, DeLaet, who has three runner-up finishes on the PGA Tour, was 2-under par heading to the final hole after recovering from a double bogey on his first hole of the day.
Paul Casey posted a 16-under score to have the clubhouse lead, a score matched by Watson through 17 holes. DeLaet who shot 67-66-64 in his first three rounds was at 15-under on the 18th hole and needed a birdie to match Casey and Watson.
Unfortunately he lost his drive into a bunker on the final hole and hit the lip of the bunker on his second shot, winding up just short of the green, but in the rough. DeLaet failed to get up-and-down for par and slipped back to 14-under. Harman's birdie on the 18th allowed him to slip past DeLaet into third place.
Watson parred the 18th and won the tournament for a second time on the second extra hole of a playoff with Casey.