How to rank up in this game?

Correct me if i’m wrong but when anyone leaves the game (enemy or not) you don’t get ranked points? I just had 4 games in a row with DCs and therefore didn’t rank up at all, and then got into a game with someone who was 10x better than everyone else in the lobby stomped and we lost, but bc no one left i was effectively 0-1 after 5 games? or am i wrong