There has not been a repeat NFL champion since the New England Patriots was able to double their pleasure in 2004 and 2005. So, how will the 2010 Super Bowl champion Green Bay Packers fare?
To repeat as the Super Bowl champion is really quite a feat
Nolan Ryan, the president of the Texas Rangers baseball team and Hall of Fame pitcher, once said: "I truly believe that repeating is the hardest thing to do in sports."
The man may have no connection to football, but nonetheless, his observation is dead-on, and it applies to Green Bay Packers, whose championship-defence phase began with a 42-34 victory over New Orleans Saints on Thursday.
In the off-season, champions usually party heartier than the rest.
They get more commercial endorsements, attend more functions, hear from relatives they thought they never had.
"Handling success," Mike McCarthy, the Packers coach, said in training camp, "is the hardest part of this business."
The last team to retain the title was New England Patriots over the 2004 and 2005 seasons.
In this parity-driven league, that is no surprise. A better measure of post-title blahs is how teams fare in the regular season. For every team such as the Pittsburgh Steelers, who followed their Super Bowl wins with non-play-off years, just as many shed their Super Bowl hangovers in time.
More recently, the Saints secured a wild card by going 11-5.
Prepared teams have learnt that it can be accomplished, and more easily than hitting a Nolan Ryan fastball in his prime.