She faced a birdie putt at the last only to three-putt for a final round of 75 and a share of third position on three-under with Mexico’s Lorena Ochoa (68) and South Korea’s Ji-Yai Shin (72).
The Mexican had made an early push for the lead, with five birdies taking her to four-under for the tournament; but a bogey on the par-five 18th ended her chances.
Sweden’s Sophie Gustafson was also among the day’s contenders, and took a share of the lead before bogeys on the final two holes sent her to two-under for the day, into tied sixth place with five other players including two-time Evian champion Annika Sorenstam.
It was second-time lucky for Gulbis after she was previously defeated at the third hole of a sudden-death play-off by Mi Hyun Kim at the 2006 Jamie Farr Owens Corning Classic.
Gulbis, who had previously been referred to as the Anna Kournikova of women’s golf due to her calendar girl good looks and lack of victories, could finally breathe a sigh of relief.
“What does it mean (to win?) How long do you have?” she said.
“This is my sixth year on tour, and obviously the U.S. has been quite a bit of hype on if I would ever win a tournament.”
It only needed one extra hole for the 2007 Evian Masters champion 2007 to be decided, with Gulbis two-putting from 25 feet at the par-five 18th for birdie and the victory.
Jang, who hit her second shot long, took a par and could only watch as the American tapped in from a foot to seal the title.
“I was really close last year where I lost a playoff, and coincidently it was right after the match play.
“It was like déjà vu,” Gulbis said.
“There was a match play event in the United States. Lost in the first round. Worked really hard on my game. Came over here was hitting the ball well, and these two events I really wanted to play well in.
“I had been injured for a lot of the season and was way back on the Money List, like 44th, maybe 50th. Probably the lowest I’d ever gotten to. Just tried to stay positive, so that means a lot, that the hard work has paid off.
“I got hurt two months ago. Had a lower back injury and had to take about a month off. I had to change my golf swing because of my injury. I had to work on my posture and I had to do all the things that I had been working on with my father for about four or five years.
“We had been working on these same things and they just weren’t happening, and it took an injury. I was kind of thinking this might be a blessing in disguise with the injury, and I kept working on it and working on my posture and I kept hitting it further and all the things I wanted to happen on my golf swing started happening.”
Gulbis was in tears as she celebrated her win with her mother, while members of the French parachute team landed on the 18th green to drape her in the Stars and Stripes of the United States flag.