There are some additional factors to take into account to decide which game you're focussing on like hrudey is saying, the place in the schedule is one of them. The amount of games you get the benefit (or penalty) for is important, so if you have another TV game coming up soon it's usually better to focus on the rival game. Another factor could be if either of the games is right before a home game and the other isn't. In isolation however (all things equal), I'd say go for the TV-game because I image that will have a bigger impact.