Ack, for me it´s the opposite. In a best case scenario I win 50% of the games when playing with 90 minutes time control (And still, thats a very optimistic win rate for me).
But, when we play the long game, I rarely loose. (With long game, I mean everything from 150 minutes to somewhere around 240 minutes when my opponents vital resources are already spent).
It might be that I tire when the game is rushed and then just throw everything at my opponent. If I roll good I might win, but most often not.