The tournament also marked the first time the 17-year-old made the cut as a pro.
Fujikawa entered the final round with a seven stroke lead over David Ishii, the 1990 Hawaiian Open champion and 14-time Japan Golf Tour winner.
He bogeyed three of the last four holes on the front nine and led by five at the turn.
But Fujikawa then shot par on eight of the back nine holes en route to becoming the youngest player in the tournaments 15-year history with a 10-under 278.
First cut as a pro, and first win as a pro. Feeling pretty good, Fujikawa said. Didnt really play too well today, it was a struggle. But luckily I grinded through it, made a lot of clutch puts toward the end.
The Moanalua High School junior made history at the Sony Open last year when he became the youngest player in 50 years to make the cut on the PGA TOUR. He was 16 at the time.
He turned professional shortly afterward, in part so he could earn enough money to travel to tournaments.
But hes struggled since, failing to make the cut at 10 pro events including five on the PGA TOUR.
Ishii, 52, praised his young rival, who took home $13,500 for his victory.
He played smart, he didnt make any foolish mistakes on the tough holes. He showed he could manage his way around Mid-Pac, said Ishii.
Ishii, a three-time Mid-Pac winner, finished second at 285. Defending champion Darren Summers (73) and 2005 champion John Lynch (75) tied for third at 286.
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