The 44 year old from India, who will captain his continent in next month's EurAsia Cup, began the week with a sparkling 62 and almost snatched victory when his eagle putt on the last lipped out before settling for birdie and a closing 68.
Frittelli was quick to pay tribute to his closest challenger.
I've set some pretty lofty goals and achieved most of them so I can't wait for 2018 - Dylan Frittelli
"Arjun Atwal - great payer, tremendous player," he said. "I played with him yesterday and it was one of the most fun rounds I've had in recent times.
"He's a player who's played all over the world, won in America, won all over the world and I'm glad I could steal one from him here.
"It's been a pretty good year for me. I've set some pretty lofty goals and achieved most of them so I can't wait for 2018 - set more goals and go and chase them again."
Having begun the day one behind leaders Atwal and Louis De Jager, Frittelli birdied the second but failed to get up-and-down at the fourth to hand the shot back.
Frittelli chipped in for an unikely par at the sixth, picked up another shot at the seventh and got up-and-down from a bunker at the ninth before chipping close at the tenth for back-to-back birdies.
Another birdie at the 14th put him in control, but after missing out on a gain at the par five last, the door was left ajar for Atwal who was a whisker away from walking through it after a superb approach to 20 feet at the 18th.
France's Romain Langasque, playing on a tournament invite after losing his card at the end of last season, recorded his best European Tour finish as a 67 saw him finish third on 14 under.
Earlier a late charge from Louis Oosthuizen had lit up the final round.
Former Open champion Oosthuizen began his final round six shots back and there was little sign of a late title tilt when he turned in a one under par 34.
However, the South African started for home with a hat-trick of birdies and then hit a spectacular second to the par five 14th to set up his second eagle of the day.
His challenge ended as abruptly as it had began, with a wayward shot finding trees on the 16th and leading to a triple-bogey seven, as he eventually finished tied for seventh after a 67.
|4||DE JAGER, Louis||RSA||18||-13|