The National Football League is famous for its competitive balance; the last 10 Super Bowls have been won by seven different franchises. But some are more equal than others.
A neutral at the start of the season would probably have gone for the San Francisco 49ers and the Seattle Seahawks in the NFC, and the New England Patriots and the Denver Broncos of the AFC as the best four teams. And lo and behold, here they are on the play-offs championship weekend, with a place in the Super Bowl at stake – offering the best two rivalries in the game, one personal and one geographic.
The former belongs to the AFC. Over the last 10 years, Tom Brady of the Patriots and the Broncos' Peyton Manning have been the league's two best quarterbacks. The pair won six MVP awards between 2003 and 2010. Brady collected two, Manning won four.
Head-to-head, however, Brady has the edge, winning 10 of their 14 match-ups. And it was the Patriots who prevailed in their one 2013 meeting, a 34-31 thriller decided by a New England overtime field goal.
On paper, therefore, Sunday's first game could not be more finely balanced. The Broncos have home field advantage, the league's most potent offense and the bookmakers' odds on their side.
And at least the Patriots do not have a stadium to play against as well – which cannot be said for the 49ers as they take on the Seahawks in the bedlam of CenturyLink Field, home of the loudest crowd in any US sport, collectively known throughout football as "the 12th man".
"Taking the crowd out of it" is a near impossibility at CenturyLink Field, where the decibel count at one recent Seattle home game was measured at 137.6, close to an aircraft carrier's flight deck at take-off time. The crowd is one reason why the Seahawks have lost one home game in the last two seasons. But not the only reason.
Seattle may well be the NFL's best balanced team, with an offense led by quarterback Russell Wilson as well as arguably the league's toughest and stingiest defense. However, if anyone can beat the Seahawks at their own game, it's the 49ers.
"We're the two teams that everybody was looking at from the beginning," says Colin Kaepernick, the 49ers' quarterback. "It's going to be a knockout, dragout game. We're ready to go."