SANTA CLARA, Calif. -- Here is a look at what the San Francisco 49ers must do and must not do Sunday at home against the Carolina Panthers:Must happen: Stick to their game plan. The 49ers are one of the best teams in the NFL. They run the ball on offense and they stop the run on defense. They need to just play their game and they should be fine. The Panthers are hot and they are dangerous. But San Francisco is the better team and if the 49ers stay the course they should extend their win streak to six games with big games against the New Orleans Saints and the Seattle Seahawks looming.