1. Marshall Newhouse vs. Justin Smith—The 49ers move Smith around, but the blind side is where pass protection is most critical, and that makes the Packers left tackle a player of huge importance in this game. Smith is relentless. This will be an all-day event for Newhouse.

2. B.J. Raji vs. 49ers interior linemen—Stopping the run always begins with plugging the middle, and that means Raji has to refuse to be moved by the double-team blocks the 49ers will throw at him. Stopping the run is critical to beating the 49ers, a team that is committed to the run, lives on the run and feeds off its energy. It’s also about time of possession. The 49ers want to run the ball and keep Aaron Rodgers on the bench.

3. Clay Matthews vs. Aldon Smith— Each is his team’s playmaker on defense. They won’t face each other, but the challenge is for one to make more big plays than the other.

4. Packers interior linemen vs. Patrick Willis—The 49ers inside linebacker is a tackling machine. The running game will be no factor unless the Packers block Willis. He can be a disruptive force.

5. 49ers nickel and dime vs. Packers receivers—Which unit is deeper, the 49ers secondary or the Packers receivers? If the Packers can find an edge with their deep and talented receiving corps, Rodgers might start 2012 as he did 2011.

Additional coverage - Sept. 7