Despite going 4-1 against playoff teams during the 2011 season, there was a sizable amount of speculation that a more difficult schedule would be the San Francisco 49ers' undoing in 2012.
As fate would have it, the NFL scheduled the defending NFC North Champion Green Bay Packers on the road in Week 1, directly followed by the home opener against the Detroit Lions, a wild-card team that won 10 games in 2012.
San Francisco responded by emerging victorious in both of these early tests, seemingly eager to prove that they aren't a one-hit wonder. After knocking off two playoff teams from last season in its first two games, it's become clear that Jim Harbaugh's squad can compete with anyone.
However, conventional wisdom would suggest that the 49ers will not remain undefeated over the course of a 16-game schedule (sorry, but somebody has to say it). With several 2011 playoff teams on the slate for the rest of the season, it's reasonable to see the team falling a few times on the way.
With these two big hurdles already out of the way, these are the five toughest challengers facing the 49ers over the remainder of the 2012 regular season.