Here is a look at what the San Francisco 49ers must do and can't do Sunday at the Carolina Panthers in the divisional playoff round:Must happen: Disrupt Cam Newton. The 49ers kept Newton from having a big day when the Panthers beat the 49ers 10-9 in November. While the Panthers still won, containing Newton again is the 49ers' best avenue of winning this game. Points will be at a premium again, so the 49ers can't allow Newton to get hot.