The Super Bowl FPI favorite is ...

Ron Rivera's Panthers were 15-1 and Bruce Arians' Cardinals were 13-3 in the regular season. Getty Images, USA TODAY Sports

ESPN’s Football Power Index favorite to win the Super Bowl is not the team that is No. 1 (Panthers) ... or No. 2 (Broncos) ... or even No. 3 (Patriots) in ESPN.com’s Power Rankings.

Instead, FPI favors, by a fairly wide margin, the Arizona Cardinals to win Super Bowl 50. Arizona has a 29 percent chance to win the title, followed by Carolina (20 percent), New England (18 percent) and Denver (11 percent).

For anyone following FPI throughout the season, this should not be a surprise. The Cardinals have ranked in the top two of FPI for 15 straight weeks and have held the No. 1 position since early December.

Even after their 30-point home loss to the Seahawks, the Cardinals remained atop the rankings (though the gap has narrowed) with the best chance to win the Super Bowl.

What does FPI see in the Cardinals?

First, Arizona is perhaps the most complete team in the NFL. The Cardinals have ranked in the top five in offensive and defensive efficiency for 15 straight weeks and are projected to have the most efficient offense and third-most-efficient defense of any playoff team this postseason.

It’s easy to focus on Arizona’s most recent loss, to the Seahawks, but that is one game in a 16-game sample. In their other 15 games, the Cardinals were the most dominant and consistent team in the NFL.

Entering Week 17, Arizona had an NFL-best plus-13.7 scoring margin and won six games by at least 23 points, tied for the most in a season since the 1996 Packers.

Although some quarterbacks have had better six- or seven-game stretches than Carson Palmer, no quarterback was more consistently efficient over the course of the entire season. He led the league in Total QBR and became the first player since Tom Brady in 2007 to post an above-average QBR in each of his first 15 games.

Another key to FPI’s Super Bowl projection is Arizona’s path to the NFC title game. By finishing as the No. 2 seed in the NFC, the Cardinals avoid Seattle in the division round; the Seahawks are perhaps Arizona’s biggest threat in the playoffs. Instead, the Cardinals will face the Vikings, Redskins or Packers. FPI gives the Cardinals at least a 75 percent chance of beating each of those teams at home.

As a result, Arizona is far more likely to make the NFC Championship Game (83 percent likely) than the Panthers (68 percent likely) because they avoid a potential rematch with Seattle.

If the Cardinals meet the Panthers in the NFC Championship Game (57 percent likely), FPI sees that game as fairly even, but given Arizona’s higher likelihood of making the game, it is the favorite to win the NFC.

Looking ahead to the Super Bowl, FPI projects the most likely Super Bowl matchup features Arizona and New England (17 percent likely). If those teams meet for the championship, FPI would give the Cardinals a 60 percent chance to win and hoist the Lombardi Trophy for the first time in the history of the franchise.