He shot a closing 1-under-par 70 to finish 9-under-par 275 overall, escaping with his first European Tour victory when rookie Andrew Tampion of Australia also bogeyed the tournament's 72nd and final hole.
The players had come to the 18th hole one-shot apart.
"I think it is a big thing for Finnish golf," said Ilonen, who is the first player from his country ever to win on the European Tour. "Golf is growing in Finland."
Ilonen had taken sole possession of the lead with a birdie at the par-three 12th hole, but Minoza tied him one hole later.
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