Control the clock by running the football
Starting fast doesn't necessarily mean scoring fast. Sure, the Packers will be delighted if they score a 75-yard touchdown on the opening play of the game. Who wouldn't be? But controlling the clock is important when facing a high-powered offense like the 49ers'.
Again, this has been the blueprint for Green Bay's success in its upset victories over Kansas City and Dallas.
Against the Chiefs, the Packers began the game with a 13-play touchdown drive that took almost eight minutes off the clock. Their opening score against the Cowboys also took over half of the first quarter.
You don't want the 49ers to have possession after possession against Joe Barry's defense. They can score quickly. Green Bay's offense can prevent that by keeping Brock Purdy and his superstar supporting cast off the field. In Week 13, the Chiefs only had two first-half possessions. The Packers held them to two field goals, entering halftime with a 14-6 lead.
The Packers don't want this to become a high-scoring, back-and-forth battle of the offenses. If they can take an early lead and drain the clock in doing so, they put all the pressure on Brock Purdy and the 49ers' offense to score touchdowns on fewer possessions than they anticipated.
It's worked for the Packers already this season. They'll need to follow a similar game script to upset the 49ers.