Another 19-year-old, centre Curtis Scott, scored a try in each half also in his first match of the year for the home side, while 21-year-old livewire hooker Brandon Smith got in on the action with a second half try.
Melbourne were missing five Maroons including big guns Cronk, Cameron Smith and Billy Slater, while the Cowboys were without Johnathan Thurston among four State of Origin representatives.
Despite the weakened line-ups and some criticism of the scheduling of the contest in the middle of the Origin series, it was a quality game.
Three Storm tries in a six-minute period midway through the second half stunned the visitors, and they looked to have the win in hand.
Smith, Scott and Felice Kaufusi all crossed to deliver an eight-point lead.
It looked like that would be the final score before the Cowboys' final flourish - and then Croft showed his mettle under pressure.
- AAP