Singh shot a three-under 69 to win the 84 Lumber Classic. He finished at 15-under-par 273, one stroke better than runnerup Stewart Cink.
This season has outstanding for Singh. He captured the PGA Championship and took over the No. 1 ranking in the world.
Singh held a two-shot lead over DiMarco to start fourth round.He wound up with his eighth victory of the season and a new single season earnings record.
"You're not really thinking about it when you're out there," said Singh, who won for the 23rd time on the PGA Tour.
Beyonce flaunts bikini body, Blue Ivy in vacation pics
Couple mistakenly served bag of cash at McDonald's drive-thru