You always have to keep the main rule about matchmaking in mind. Matchmaking always attempts to match the inept players on your team, and the skilled players on the enemy team. You only win games because the enemy has a disconnected player or throws the game.
Had a Dominion game where I had to restart my client twice, one due to it freezing after champion select, and the other because my router decided to stop working. Somehow we won that game because our Diana got really fed, but having two disconnects like that in Dominion out of all places is usually VERY punishing.