expression
victory is mine; with this, I'll win
Internet slang, often used playfully or triumphantly when one feels they have secured a win or advantage. The form 勝つる is a deliberate archaic-sounding or emphatic variant of 勝つ.
相手がミスった！これで勝つる！
My opponent messed up! Victory is mine!
この作戦なら、これで勝つる。
With this strategy, I'll win.