Graeme McDowell clenches his fist to celebrate his birdie at the 18th. But will it prove crucial on Sunday?Graeme McDowell refused to go away as Charley Hoffman had just 21 putts to take a two -shot lead in the final round of the RBC Heritage in Hilton Head.

The Ulster player holed a 12 footer at the last for a three under 68 that left him just four adrift of Hoffman at Harbour Town Golf Links in South Carolina.

The two-time PGA Tour winner birdied four of his first five holes and shot a five under 66 to lead by two strokes on 11 under from US Open champion Webb Simpson, who shot a 65.

Kevin Streelman is another stroke back after a 69 with McDowell and Brendon de Jonge tied for fourth at seven under while eight others, including Ryo Ishikawa, Camilo Villegas, Billy Horschel and Bill Haas, are tied at six under.

McDowell, who is seeking his first official win on US soil since the 2010 US Open, birdied the first from six feet but couldn’t get up and down from greenside sand at the third.

However, he was soon back in touch, draining a 25 footer at the fifth and a 20 footer at the next before following a run of 11 consecutive pars with that birdie at the 18th.

Hoffman did not have a great day from tee to green but holed everything in sight and believes he coming to terms with the tight fairways and small greens at the Pete Dye track that caused him major problems earlier in his career.

“I guess I wasn’t mature enough to play this course,” Hoffman said. “Once you learn what side of the fairway to leave it on and where to miss, you have a real big advantage.”

Hoffman hit just eight greens but had just 21 putts as he made five birdies in an error free round.

“It's a work week, but it's no hard work week,” McDowell said after joining Brendon de Jonge at 7 under par. “This is really a fun week, really, really chill and laid-back, especially coming off the back of last week. It's just show up, warm up, go play, get your job done and then go back and get your feet up and enjoy the views and have some family time.”

Pleased with his closing birdie McDowell told

“That always makes dinner taste good, that old cliché,” McDowell said. “I felt a little off my game and couldn't seem to quite get it going, just trying to force the issue. I didn't quite strike it as pure as I have the last couple of days, kind of had 15 feet (on putts) all day and couldn't make anything. But I hung tough and have a chance going into the final round.”

McDowell downplayed any advantage of having honed his game on his native windblown Irish links, saying there are a lot of good wind players on the PGA Tour. He does, however, hope that the overnight forecast for high winds holds up and would like nothing more than a gusty final round.

“What the wind does is keep everyone honest,” McDowell said. “(Saturday) I'd call it a fairly level playing field, there were 64s and 65s out there and that's not what we expect on this golf course. We expect a tougher challenge (Sunday) and it will separate the men from the boys. The guy who wins it will earn it.”