Stewart Cink cruised to a four-stroke victory as he clinched his third RBC Heritage crown on Sunday.

Winner of the PGA Tour tournament in 2000 and 2004, Cink completed the treble after carding a one-under-par 70 in the final round.

Cink had two birdies and a bogey to finish 19 under, ahead of countryman Harold Varner III (66) and Argentina's Emiliano Grillo (68).

It capped a memorable week for Cink at Habour Town, where the American set the lowest 36- and 54-hole score at the RBC Heritage of 126 and 195 respectively, en route to glory.

"I don't even know if I have the words," Cink said after having his son Reagan as his caddie.

Cink became the seventh player to go 21 years or longer between his first and most recent victory at the same event on Tour.

With the triumph, Cink also became the fourth player (fifth instance) aged 47 or older to win multiple times in a season on Tour since 1960, joining Sam Snead, Julius Boros and Kenny Price (twice), after taking out the Safeway Open.

Aged 47 years, 10 months and 28 days, Cink is also the second oldest RBC Heritage champion following Hale Irwin (48 years, 10 months and 14 days in 1994).

Webb Simpson, who was the defending champion, finished tied for ninth and eight shots off the pace following a final-round 70, while world number one Dustin Johnson (66) was a stroke further back.

"I just feel like I made way too many mistakes," said Johnson, who missed the Masters cut. "Around here, you make mistakes, they penalise you pretty big."