A hat trick from winger Tony Tumusa and a strong second half performance has helped the U20 Thunderbolts to a 40-18 win, their eighth of 2015.
Holding off a surge from the Dragons late in the contest, Marc Brentnall's side counterpunched into the wind scoring four tries to three in the second stanza to build on their half-time advantage.
Earlier, Tumusa helped get the home side off to a strong start on Gosch's Paddock, scoring the opening two tries of the contest to get his side on the front foot. A strong Charlie Galo run and four pointer late in the half ensured Melbourne would take an advantage into the break.
Needing to work hard running into a strong breeze in the second half, the Thunderbolts did not rest on their laurels as they opened the scoring after half-time to extend their lead. After Tumusa completed his hat trick, Aiden Taua crossed for his first NYC try to put the hosts in the box seat.
A late charge which included three tries for St George Illawarra was not enough for the visitors as the young Storm side held on to be 40-18 victors.
The U20 Thunderbolts will travel to Leichhardt Oval next Friday to take on Wests Tigers in Round 21.
Melbourne Storm 40
Tries: Tony Tumusa 3, Charlie Galo, Aiden Taua, Junior Kirisome, Shae Ah Fook
Goals: Mack Mason 6
St. George Illawarra Dragons 18
Tries: Izaac Thompson 2, Dee Jay Harris 2
Goals: Ryan James 1