Artis shot a six under par 66 "“ the lowest round of the tournament - in blustery, drizzly conditions at Dundonald Links in North Ayrshire to finish on six under par and two shots ahead of Pettersen, the world number seven.
England's Holly Clyburn ended two shots further back in third ahead of Klara Spilkova and world number two, Lydia Ko.
"Sometimes you fight all your life to try and get that first win and sometimes the second win is maybe even harder," said Artis, 26, from Coonabarabran, who won in similar conditions at the Helsingborg Open in Sweden two years ago when she came from five strokes behind Caroline Hedwall with a final round of 69.
"I've been playing some really consistent golf since the start of the year, putting myself in contention week in, week out. I knew that with the conditions the way they were predicted to be today that if I went out and played some solid golf, then I wouldn't be far away.
"I've got my coaches over here from Australia, Gary and Luke Edwin. Whenever they're around I feel like I go to a new confidence level with my overall game."
Artis birdied the par-five third and then double bogeyed the short fourth in the final round, after hitting her tee shot right with a 5-iron, but she immediately recovered with back to back birdies on the fifth and sixth, before picking up another shot at the eighth.
"To come back and birdie five and six straight after that was huge to get the momentum back on track and not let it bother me," said Artis, who made four further birdies on the back nine. She fired three in a row from the 12th and chipped in from 10 metres on 16.
Moments later, Pettersen bogeyed 16 to drop one behind the lead and needing to birdie the par-5 last to tie, she then sent her ball into the burn guarding the green with her second shot from 200 yards, resulting in a costly bogey.
"I played pretty well today and gave myself a lot of chances. It was not on the easy side. For Artis to shoot 66, definitely deserves to win," Pettersen said.
"I had my chances. I bogeyed 16 and had a look at 17 after two great shots. 18 I miscalculated. It was more into and the ball spun up on me. I had to give it a go. Eagle would win it, birdie would tie. It's fine."
Despite keeping pace with Pettersen throughout the final day, Clyburn was disappointed with a 74, containing three bogeys on the back nine. "Tee to green I was fantastic and up to par with Suzann but didn't putt very well," she said.
Ko was happy enough with her 74 and said: "I think it was good preparation for the Women's British Open. I don't know what the weather will bring next week but that was the big thing: to get more experience playing links golf. I think it was great."
With a career best tie for fourth place, Klara Spilkova was one of the three players that gained an exemption into next week's RICOH Women's British Open at Turnberry, along with Hannah Burke, who finished sixth and Jade Schaeffer, who tied for 14th place.
Artis had already qualified for the Ricoh Women's British Open and her parents, who are flying over from Australia to watch her play, will have a pleasant surprise when they land in the United Kingdom.
In the meantime, with a cheque for 75,000 euros, Artis and her husband Geoff, who is her full-time caddie, will be able to celebrate the victory a day after his 31st birthday.
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