At the beginning of the season we had 4 games scheduled against teams that were considered to be SB contenders in KC, Seattle, San Fran and Pittsburgh. So far we're 2-1 in those games with the caveat that we didn't get the 49ers' SB capable roster (on the other hand the Rams are now considered a contender and we beat them too so...)
In other words you won't catch me fretting over a loss on Sunday but a win would be enormous.
Frankly I think we already played the most important game of the season against Seattle. We were 2-2 in the previous 4 games with less than convincing wins over the Pats and Jets and the narrative of a season that might go south vanished after we pounded on them.