Pettersen never flinched down the stretch, closing with a 5-under 67 to hold off a spirited challenge by Karrie Webb and a late charge by 18-year-old Na On Min for a one-shot victory and her first major championship.
The 26-year-old Norwegian had ample opportunity to fold at Bulle Rock, but she didn't budge. She hit the ball so purely that she never missed a green on the back nine and only twice had a birdie putt longer than 12 feet. One of those was on the final hole, when she had two putts from 30 feet for the victory.
The pace was perfect -- just like everything else on the back nine -- and settled 3 inches from the cup.
It was nothing like her performance at the Kraft Nabisco Championship, when Pettersen squandered a three-shot lead over the final four holes with two bogeys and a double bogey, a collapse that left her in tears.
She bounced back to win the Michelob Ultra Open a month later, then removed any doubts about her psyche at Bulle Rock.
Webb, a runner-up for the second straight year, made her earn it. The seven-time major champion made a clutch par from the bunker on the 16th, then closed with two straight birdies for a 67.
'I knew what happened to her at Kraft, and I just knew I needed to keep putting pressure on her,' Webb said. 'She obviously executed very well coming down the stretch, and she should be very proud of herself. It shows a lot of courage and guts and trust in her ability.'
Min, trying to become the youngest major champion in LPGA history, ran off four straight birdies on the back nine to get within one shot, but settled for pars on the last two holes for a 70 to finish third in her first major championship.
Pettersen made four birdies on the back nine, none bigger than a 12-footer on the 17th to give her a cushion going to the final hole. She finished at 14-under 274 and earned $300,000 to over $1 million for the season.
Lorena Ochoa remains No. 1 and without a major. She was close enough to make a move, one of eight players separated by three shots at various stages of the back nine, but missed key birdie chances and had to settle for 69 and a tie for sixth, six shots behind.
Michelle Wie completed an acrimonious stay at Bulle Rock with a small consolation -- her first performance-based paycheck of the year.
'It's a good feeling to get a paycheck,' she said with a laugh.
Then again, she had to make an 8-foot bogey putt on the final hole to break 80, it was her 20th consecutive round without breaking par, she finished in last place by 10 shots, and her 21-over 309 was the highest 72-hole score of her career, professional or amateur.
'I think it was a good decision (to play), but also maybe a couple of weeks too early,' Wie said. 'I have to test the waters sometime. I felt like this week is a lot better than last week, and I hope the U.S. Open is going to be a lot better.'
The Women's Open is in two weeks at Pine Needles.
The teenager who stole most of the attention through three days was Min, an 18-year-old from South Korea who had a one-shot lead as she tried to become the youngest LPGA major champion in history. She got plenty of breaks early, making par from the bunker on the opening hole and building a two-shot lead with a birdie on the fourth.
But the lead was gone in two holes, and soon she was an afterthought.
Pettersen hit an approach into 2 feet on the uphill fifth to get within one, then let Min retreated. The teenager missed two straight par putts inside 4 feet, then failed to get out of a greenside bunker on the par-5 eighth and took another bogey. Min didn't make another birdie until the 13th hole, and then she couldn't miss.
Most of the back nine was a duel between Webb and Pettersen, with the Norwegian in the final group and always in the lead.
Webb got to within one shot with a 40-foot birdie on the 11th, and Pettersen answered with an 8-foot birdie on the 13th. Moments later, Webb made an 8-foot birdie on the 14th.
The pivotal hole was the par-5 15th, which can be reached in two with a good drive.
Webb didn't hit one. She pushed it into the right rough, had to chip out short of the hazard that left her 207 yards away and did well to make par. Pettersen found the fairway and the green, and two-putted for birdie to lead by two with three holes to play.
'One shot -- I'll be thinking of a lot of places where I could have made that up,' Webb said.
Pettersen won't have to think about Kraft Nabisco until she returns to the California desert next year as a major champion.