The 49ers’ showdown with the Baltimore Ravens quickly became their most important contest of the year after the Seahawks and Saints both earned victories last weeks. San Francisco enters Sunday’s game in Baltimore with their first-round bye and home field advantage potentially on the line.

Here’s what’s at stake for the 49ers on Sunday:

With a win…

With a win the 49ers stay on top of the NFC and the NFC West. They also start 2-0 through that vaunted three game stretch vs. the Packers, Ravens and Saints.

San Francisco legitimized themselves as contenders in the NFC with their 37-8 thumping of Green Bay last week. They can leap to Super Bowl favorites if they knock off the Ravens.

A win would also be a step toward clinching a playoff spot. They can do so in Week 13 with victory and a Rams loss or tie.

With a loss…

A loss puts a couple of bad things into play. First, falling to 10-2 would allow the Seahawks to jump into first in the NFC West, and second place in the NFC. Seattle holds the tiebreaker with San Francisco, so they’d switch spots with the 49ers if they beat Minnesota on Monday night.

Moving to the No. 5 seed means the 49ers would lose home field advantage and their first-round bye.

Winning the NFC West is going to be imperative, and a loss Sunday puts immense pressure on the 49ers to stay in lockstep with Seattle until the two teams face off in Week 17. Ideally, that final game would be meaningless for the 49ers and they could rest their starters to get ready for the postseason. A loss to Baltimore puts that scenario much less realistic.