HILTON HEAD ISLAND  - Sweden’s Carl Pettersson fired a two-under par 69 in Sunday’s final round to win the $5.7 million US PGA Heritage tournament by five strokes over American Zach Johnson.Pettersson won the $1.026 million top prize and his fifth career US PGA title, his first since capturing the 2010 Canadian Open, to match Jesper Parnevik for the most career US PGA triumphs by a Swedish player.“It wasn’t easy,” Pettersson said. “I focused and I got it done. It was a great day.”Pettersson finished 72 holes on 14-under 270 with American Johnson, the 2007 Masters winner, a distant second on 275 after a final-round 70.American Colt Knost was third on 276, his best US PGA finish in seven tour seasons despite a last-round 74. Americans Kevin Stadler and Billy Mayfair were next on 278.Pettersson birdied three of the first five holes, opening with a birdie and adding two more on the par-3 fourth and par-5 fifth.When Knost, the Swede’s only rival within four shots when the day began, triple-bogeyed the par-4 third, Pettersson was staked to a huge edge on the field and followed with nine pars in a row before taking a bogey at 15.“I had it on cruise control on the front nine,” Pettersson said. “I knew 14 was a tough hole and 15 ended up biting me again.”Johnson, the 2007 Masters champion, was the only rival to make a run with birdies at the par-5 second, par-3 fourth and par-5 fifth. He answered a bogey at the par-3 seventh with a birdie at nine but took another bogey at the 10th.A birdie at the par-5 15th allowed Johnson to pull within three strokes of Pettersson, but Johnson took a bogey at the par-4 16th and Pettersson escaped a divot worry at the 16th with a par to stay ahead by four.Johnson finished with a bogey and Pettersson parred 17 and 18 to complete the victory.