How did we win this game?

This match started horrible, first we had no adc so i went bot only to get destroyed by a bot and every other lane lost with us. We somehow made it to a point that we ended up all diving the nexus with an entire full built team and we ended the game off that. This reason i ask why we won is because for the entire game we were behind in almost every aspect of the game wither it was items, gold, or skill. I just have no idea how we won. Does anyone else think we should have won this?