Hart and DiMarco outlasted Stewart Cink and Jeff Toms in the two-day better- ball event at the Rhode Island Country Club. Hart and DiMarco took home $230,000 of the $1.2 million purse.
Hart's eight-foot birdie on the last hole of regulation got his team to 20-under 122 and forced a tie with Cink and Toms, who set a tournament record with a 14-under 57 in the second round. On the third playoff hole, Hart drained a 25-footer for birdie.
Cink just missed on his birdie attempt at the 18th hole that would have forced a fourth extra hole.
Each team parred the first playoff hole. Cink then rolled in a seven-footer for birdie on the second hole, but Hart matched that with a six-footer.
Hart and DiMarco were tied with defending champions Mark Calcavecchia and Nick Price after Monday's opening round at 11-under 60. However, Calcavecchia and Price could only manage par on each of the holes on the back nine after going 17-under through the first 27 holes.
The team of Steve Elkington and Craig Stadler tied for third at 18-under with David Duval and Peter Jacobsen.