Kenny Huether scored the winner in overtime and Jeremy Brodeur made 19 saves in relief as the Generals topped Guelph.
Anthony Cirelli, Domenic Commisso, Jack Studnicka and Danil Antropov supplied the rest of the offence for Oshawa (7-5-0). Kyle Keyser started but was lifted after turning aside 11-of-14 shots in the first period.
Isaac Ratcliffe, Nic Sicoly, Givani Smith and James McEwan had goals for the Storm (5-6-2). Liam Herbst stopped 31 shots in net. The Storm took five of six points over the weekend with wins Friday and Saturday over North Bay and Barrie.
And in Junior B hockey action, the Guelph Hurricanes fell to the Waterloo Siskins 2-1.