Day and Tringale began the day with a three-shot advantage in the two-man competition but were caught by defending champs Matt Kuchar and Harris English, who shot a 10-under 62 in best-ball during the final round. Tringale's short birdie putt on the par-5 17th put his team back ahead, and a par on the final hole sealed a one-shot victory after a final-round 65 gave the duo a three-round total of 32 under.
The unofficial victory is the first for Tringale as a pro, while Day already has two PGA Tour wins to his credit.
A two-way tie for third featured Keegan Bradley and Camilo Villegas along with Billy Horschel and Ian Poulter. Both teams shot 11 under in the final round to get within three shots of the eventual winners.
Graeme McDowell and Gary Woodland began the day closest to Day and Tringale but combined for a 6-under 66 to finish four shots back, with Woodland battling a potential back injury for much of the day. The lowest final-round score came from Steve Stricker and Jerry Kelly, who fired a 12-under 60 to tie for fifth.
Day and Tringale are just the fourth team to win this event in wire-to-wire fashion and the first since Fred Couples and David Duval did so in 1999. Their 17-under 55 in the first round under scramble rules tied a tournament record, and they followed it with an 8-under 64 in alternate shot during the second round.