The 17-year-old, who lives in California, carded rounds of 70-70-69 at Leilehua Golf Course for a seven-under-par total to claim his second success in the tournament by four shots.
In the closing circuit, Shiels Donegan was out in one-under before picking up birdies at the 11th and 16th holes on the inward journey.
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Hide AdThe polished performance earned him a comfortable victory over three Hawaiian players - Joshua Hayashida, Isaiah Kanno and Katsuhiro Yamashita.


Shiels Donegan, who is a member of Mill Valley Golf Club in a city just north of San Francisco, spent a fair bit of time playing in the UK last summer as he was accompanied on a trip by his parents.
He finished second in the Carris Trophy, which is the English Boys’ Under-18 Championship, and also claimed a top-ten position in the East of Scotland Open.
On the team front, he represented Scotland in the European Boys’ Championship in Germany and also the Boys’ Quadrangular in Wales.
In addition, he was handed the honour of captaining Great Britain and Ireland in the Jacques Leglise Trophy against Continental Europe at Blairgowrie.
Last November, Shiels Donegan finished second in the Gobbler Amateur, a World Amateur Golf Ranking event at Sewailo Golf Club in Tucson, Arizona.
In his last seven competitive rounds, which have been over three events, he is a combined 18-under-par.