The Northern Irishman became the first European to triumph on the PGA Tour this year with a narrow victory over the American at Hilton Head.
"I played nicely, I played nicely all week," McDowell told Sky Sports News.
"It's a great golf course around here. I sat around with Jim Furyk earlier this week at a Q&A and he said you're never out of this tournament, you just have to hang around. I did that."
McDowell's last success on the PGA Tour came with victory at the US Open in 2010.