The 158th-ranked Australian came through the qualifiers and only dropped one set on her way to the final.
Barty, 20, says "I was just so happy to come out and play some good tennis today."
She raced to a 4-1 lead in the opener before a heavy downpour halted play for almost 90 minutes at the TPC Kuala Lumpur.
Barty returned with the same power and consistency to take the first set.
Hibino's unforced errors continued in the second set, with the Japanese unable to cope with Barty's precise forehand strokes.