I actually think it does, for two reasons. First, contrary to what we might like to believe, negative campaigns in general work. We keep seeing ads that bash the other candidate, in greater proportions year after year, because attacks on the opponent tend to be more effective than glowing commendations for oneself. It's a lot easier to win when you're on offense, scoring points against the opponent, rather than backing into a defensive corner.
Second, and perhaps more importantly, Ryan spent a substantial portion of the debate focusing on foreign policy. Specifically, he preached strength. Yet Biden overpowered him. It looks bad to argue that you're going to take a stronger stance in the international community, then allow your opponent to steamroll you. It makes it look like your claim of strength is invalid.