Here's a key matchup to watch in Sunday's Vikings-Broncos game.

Vikings QB Christian Ponder vs. Broncos defense

Ponder has a tough matchup this week, going against a resurgent Broncos defense that has been more important to their recent streak into playoff contention than Tim Tebow and the offense.

The secondary is much improved with the play from corners Champ Bailey and Andre' Goodman and the pass rush has been ferocious led by Elvis Dumervil and Von Miller.

With Adrian Peterson out for Sunday, and the downgrade to Toby Gerhart that comes with it, the weight of the offense will once again be on Ponder. He struggled in the first half against the Falcons, leading them to only five first downs, but started to generate a rhythm in the second half, especially with Percy Harvin.

The Vikings offense needs to have more success early and it starts with Ponder. He needs to move the chains early with his arm and his legs to sustain drives and give the defense rest from the punishing Broncos run offense.