"I think that was kind of the best thing about this was just we had a ton of fun, just like being a kid enjoying what you're doing," O'Hair said. Rory Sabbatini and Charles Howell III made a charge on the back nine that included an eagle on a par-4 but finished one stroke back at 30-under 186. They had a 15-under 57 in the scramble format in the final round on the Gold Course at Tiburon Golf Club.
"We played really well and gave ourselves a lot of opportunities," Sabbatini said. "We put a good number up there and that's all we can really do. We had a lot of fun and Charles hit the ball fantastically."
Jason Dufner and Vijay Singh finished third at 28 under.
Perry and O'Hair became the seventh second-round leaders to go on to win the tournament in the last 12 years. While other teams were making charges at them, and sometimes briefly catching them, they had fewer holes left to play than Perry and O'Hair.
"I knew they were going to probably catch up to us at some point, but I knew we had holes to catch back up to them," Perry said. "You can't really get too far ahead of yourself out there in that field. You just kind of play each hole."
Stewart Cink and Carl Pettersson, first-round leaders Davis Love III and Brandt Snedeker, and 2009 champions Jerry Kelly and Steve Stricker were another shot back in a tie for fourth.
Love and Snedeker could never get going.
"We put the ball in the fairway all day, but never really got close into the greens," Love said. "We were 15 to 30 feet all day today, and we weren't as sharp this weekend as we were Friday."
Perry and O'Hair led by two shots going into the final round. They will split $750,000 of the $3 million purse.
• In Sydney, Peter Senior won the Australian Open by one stroke, overcoming severe weather conditions that forced a three-hour suspension because of gale-force winds. Senior, 53, shot an even-par 72 in the final round at The Lakes to become the oldest Australian Open champion. Senor finished with a total of 4-under 284. Fellow Australian Brendan Jones was second after a 71.