The Storm now needs to win the last two games to have a finals chance, with the weekend’s loss seeing the team slump all the way down to 10th.
The Dragons have no such issues, rising to fourth on the table on the back of a captain’s innings by Matt Johnston.
Looking in trouble at 5-152, a patient knock of 68 from 153 balls ensured Willetton passed Melville’s total of 8-269 total late on day two.
Brennan Wilson provided perfect support for his skipper, smashing an unbeaten half-century to guide his side home.
Drew Porter and Mark Turner were the pick of the bowlers for the struggling Storm, taking two wickets each.