HILTON HEAD ISLAND, S.C. —  Graeme McDowell defeated fellow U.S. Open champ Webb Simpson in a playoff to win the RBC Heritage on Sunday for his second career victory on the PGA Tour.

McDowell was four shots behind when the round started, but rallied with a closing 69 over wind-blown Harbour Town Golf Links. The 2010 U.S. Open champ had his only bogey of the day on the 72nd hole to force a playoff with Simpson, the reigning U.S. Open titleholder.

McDowell stuck his approach on the extra hole about 15 feet away and two-putted for par. Simpson could not answer, missing about a 10-footer for par. Luke Donald and Kevin Streelman tied for third.

McDowell’s win ended a tough day in which only three players shot in the 60s. Donald shot a 69 while Streelman had a 72. Jerry Kelly rounded out the top five after his even-par 71.

Charley Hoffman, the 54-hole leader, ballooned to a 77 and fell into a tie for sixth.

Both McDowell and Simpson had the chance to win on the 72nd hole. McDowell missed a 12-foot par putt after his approach went over the green. It was his only bogey on the round.

Simpson had a 22-footer for birdie a short time later on the 18th, but sent it 3 feet past to lead to the tournament’s third playoff in four years.

McDowell patted Simpson on the back after the playoff miss and smiled widely as the boats in Calibogue Sound tooted their horns and whistles.

Neither McDowell nor Simpson made the cut a week ago at the Masters, yet bounced back in a big way at Harbour Town.

The course showed its teeth, winds arcing flagsticks and blowing debris on every hole. Donald backed off his putt on No. 7 when a large leaf tumbled through his line. Crews watered several greens between groups simply to keep balls holding instead of skipping off the wind-swept sod.

Blowers were heard throughout the day, trying to push off leaves, twigs and other tree parts falling everywhere on the course.

The National Weather Service issued a wind advisory for the area, warning of winds of 20-to-30 mph and gusts up to 45 mph.

”Extremely difficult,” Donald said of conditions. ”Strongest wind I’ve played in all year.”

Few managed the wind better than McDowell, who lurked behind most of the round until striking on the back nine. He made a 28-foot birdie putt on No. 11 to move into a three-way tie for first with Simpson and Hoffman.

McDowell broke the tie on the 16th hole, landing his approach within 8 feet and making the birdie putt. He saved par from the back of the green on the 17th hole, but couldn’t do it a second time on the closing, lighthouse hole at No. 18 for his first bogey in 32 holes to fall back into a tie with Simpson.

Simpson’s chase appeared over when he made three bogeys in a six-hole stretch to fall two shots behind. He steadied himself with a birdie on No. 12 and parred his way to the finish to reach the playoff.

Donald, who’s got two seconds and a third in his past four appearances at Harbour Town, got an early charge going before Hoffman and Simpson hit the course with four birdies on his first six holes to draw within two of the lead.

Donald, ranked No. 6 in the world, couldn’t keep the surge going, though. He had birdie chances on the final three holes of the front nine, but came up empty. Bogeys on the 13th and 15th holes ended Donald’s run. Still, it was the fourth top-five finish in the last five trips to the RBC Heritage for Donald.

Saturday notes:

Leaderboard: Charley Hoffman 66-70-66—202 (-11); Webb Simpson 68-71-65—204 (-9); Kevin Streelman 66-70-69—205 (-8); Brendon de Jonge 70-69-67—206 (-7); Graeme McDowell  71-67-68—206 (-7)

Charley Hoffman

— Hoffman birdied four of his first five holes en route to a 5-under 66, taking a two-stroke lead over Webb Simpson through 54 holes at the RBC Heritage.

— With his 66 in round three, Hoffman extended his streak of consecutive sub-par rounds to 11, dating to the first round of the Shell Houston Open (T20). A week later, and in his last start before this week, he finished T3 at the Valero Texas Open.

— Hoffman’s R3 at a glance: 7/14 fairways, 8/18 greens in regulation, 21 putts.

— Hoffman leads the field this week with just 73 putts and a +3.607 average in Strokes Gained-Putting. David Frost set the PGA Tour’s all-time 72-hole putting record with 92 total putts at Harbour Town in 2005. The old mark was also set at Harbour Town when Kenny Knox had just 93 putts in 1989 (matched by Mark Calcavecchia at the 2002 Greater Greensboro Chrysler Classic).

— Hoffman is making his ninth start of the season this week, with a T3 at the Valero Texas Open his best outing.

— Hoffman is making his fourth start at the RBC Heritage (MC-2006, 75-2009, T8-2012).

— Hoffman’s previous-low round at Harbour Town was a 6-under 65 in the second round in 2012 (T8).

— Hoffman owns two wins  (2007 Humana Challenge, 2010 Deutsche Bank Championship).

— This marks the first time in Hoffman’s career he has carried the lead into the final round on the PGA Tour.

Tournament Notes:

— Since the RBC Heritage moved into its slot after the Masters in 1983 (2011 the exception when it was played two weeks after the Masters), just six players have won the event without having competed in the Masters the week before: Carl Pettersson (2012), Brian Gay (2009), Boo Weekley (2007), Aaron Baddeley (2006), Bob Tway (1995) and Davis Love III (1987).

— There are 32 players in this week’s field who competed last week at the Masters Tournament.

— Players who have made the RBC Heritage their first PGA Tour victory include Hale Irwin (1971), Graham Marsh (1977), Doug Tewell (1980), Nick Faldo (1984), Davis Love III (1987), Glen Day (1999), Jose Coceres (2001), Peter Lonard (2005), Aaron Baddeley (2006) and Boo Weekley (2007).

— Past RBC Heritage champions and their position at the time of the suspension: Jim Furyk (T51), Boo Weekley (T71), Glen Day (T59), Brandt Snedeker (T71), Aaron Baddeley (T51), Brian Gay (T51), Justin Leonard (T51), Stewart Cink (T13) and Carl Pettersson (T59).

— Nine of 14 third-round leaders have gone on to win this season, most recently Tiger Woods at the Arnold Palmer Invitational.

— The third-round lead/co-leader has won 31 of 44 times at the RBC Heritage, most recently Carl Pettersson in 2012.

— The lowest first 54-hole score at the RBC Heritage is 197, set by Justin Leonard in 2002.

— 2012 U.S. Open champion and three-time PGA Tour winner Webb Simpson carded a third-round 6-under 65 to move to second place. It equals his best round of the season, set during the third round of the AT&T Pebble Beach National Pro-Am (finished T26) and the third round of the Humana Challenge (MC). His previous-best round at Harbour Town was 68, set on three occasions and most recently in the final round in 2011 (T14).

— Two starts removed from his first-career victory at the Tampa Bay Championship, 36-hole leader Kevin Streelman sits in solo-third place in his fifth start at the RBC Heritage (best finish was T17 in 2012).

— Brendon de Jonge (T4) recorded a 4-under 67 on Saturday, marking the third time in five tries he has turned in 67 or better in the third round at the RBC Heritage, but he has never broken 70 on Sunday. He is seeking his first win in his 161^st career start.

— Graeme McDowell (T4) appears to be figuring out Harbour Town. In three prior starts, six of his 10 rounds were over 74, including a 7-over 78 in the final round in 2005. This week he owns all three rounds at par or better (71-67-68) and is in striking distance of his second  title (2010 U.S. Open).

— Carl Pettersson sits T60 in his attempt to join Payne Stewart (1989-90), Davis Love III (1991-92) & Boo Weekley (2007-08) as back-to-back winners at the RBC Heritage. He kept a 20-year streak intact this week, as no defending champion has missed the cut at the RBC Heritage since Davis Love III in 1993.

— 2012 FedExCup champion and 2011 RBC Heritage champion Brandt Snedeker made the 36-hole cut (2-over 144) and the 54-hole cut (2-over 215) on the number and sits T60.