Peterborough struck first 1:47 into the game. On the rush, Caden Taylor opted to take the shot and rifled it past Generals goalie Jacob Oster for a 1-0 lead.
It was the only goal until the early third period as Oshawa’s Luca Marrelli had the puck at the point and was able to snipe it through traffic for a 1-1 tie.
The game needed overtime to decide a winner but it gave the Petes their first point of the season after they had been held without one in seven games.
It only took 25 seconds to finish overtime as Lauri Sinivuori in a two-on-two, received a saucer pass and rifled it top shelf for the walk-off goal and a 2-1 win.
The Petes can get revenge on the second half of the home-and-home series as they travel to Oshawa to face the Generals on Friday night. Puck drop is at 7:05 p.m.