Which team defeated the 49ers by 34-31 in the 2013 Super Bowl?
2012 San Francisco 49ers season:  However, the season ended with their first-ever defeat in the Super Bowl, falling to the Baltimore Ravens, 34-31. Super Bowl XLVII:  The Ravens defeated the 49ers by the score of 34–31, handing the 49ers their first Super Bowl loss in franchise history.
Baltimore Ravens