The victory earned Gay a trip to next week's U.S. Open at Bethpage Black.
"I don't know if we'll go home or straight up there tomorrow or what," Gay said when asked about his last-minute trip to New York. "I've got a lot of stuff with me and a lot of dirty clothes."
Gay was a model of consistency during the tournament despite stormy weather that delayed Sunday's round. He shot a 64 Thursday and then went on to card the consecutive 66s.
"I putted great," said Gay. "I hit my irons pretty well. I didn't have my best game off the tee with my driver. I hung in there."
He began play Sunday with a one-stroke lead over Molder but birdied the second hole and then the fourth on a clutch 20-foot putt while Molder carded a bogey.
After sinking another long birdie putt on the sixth, Gay bogeyed No. 10. He responded by nearly acing the 11th hole. He finished the round with a birdie on the final hole.