The 29-year-old world number 133, two shots back overnight, carded a bogey-free seven under 64 to reach 21 under.

It gave him a two-shot victory ahead of Russell Henley, who had 10 birdies in a 61 at TPC Deere Run in Illinois.

Frittelli has played in the last two Open Championships and he failed to make the cut on both occasions.

A superb bunker shot on the opening hole gave him a tap-in birdie, the first of three in succession on the final day in Silvis.

Henley made six putts of over seven feet in his tournament-best round, including efforts from 26 and 46 feet, to set the clubhouse target at 19 under.

Frittelli birdied the par five 17th after playing out of a greenside bunker to 11 feet to ensure a comfortable finish, and looked forward to the tournament's charter flight to Royal Portrush.

"Hopefully I can be calm by the time I get there but I'm sure it's going to be a fun flight," he said, ahead of Thursday's opening round in Northern Ireland.