There have been several instances down the years of teams upsetting the odds and unexpectedly winning the NFL Championship.
Let’s take a look at the five unlikeliest NFL Championship winners in the league’s history.
Read more: Greatest NFL Championship performances of all time
Starting the season 7-5 likely won’t make you an NFL Championship favorite. That was the case for the Pittsburgh Steelers in the 2005-2006 season, but after a second-half surge, the Steelers were 11-5 heading into the playoffs.
However, Pittsburgh had a gauntlet of a schedule ahead of them. They had to play the #1, #2, and #3 seeded teams in the AFC before even thinking about the NFL Championship.
In true underdog fashion, the Steelers became the first team ever to beat the three top-seeded teams in the conference to advance to the NFL Championship. It was there that the Steelers beat the NFC Champions, the Seattle Seahawks, in a 21-10 game.
A slow start to the season and a difficult playoff schedule were just a few parts of Pittsburgh’s magical season.
The legend of Tom Brady began in the 2001-2002 season. Brady, a sixth-round pick, was the backup to start the season.
However, starting quarterback Drew Bledsoe suffered an injury in the second game of the season, and that’s when Brady took over the starting job and never gave it back.
The rookie led the Patriots to an 11-5 record, and the infamous 'Tuck Rule' game took place in New England’s win over the Oakland Raiders in the AFC Divisional game.
The rookie’s success was expected to end in the NFL Championship against the St. Louis Rams, a team that earned the nickname 'The Greatest Show on Turf'.
The Rams were 14-point favorites in the NFL Championship, but a terrific game from eventual championship game MVP Brady led to a 20-17 win for the Patriots to cap an incredible underdog story.
Aaron Rodgers and the Packers had a decent regular season, but a 10-6 record and being slotted as the #6 seed doesn’t indicate you have a great chance of being the last team standing.
However, the Packers beat the Philadelphia Eagles, Atlanta Falcons, and Chicago Bears. Just like that, the sixth seed was in the NFL Championship.
On the AFC side, the Pittsburgh Steelers had gone 12-4, won the AFC Championship, and Ben Roethlisberger was looking elite once again heading into the clash.
And for the second time ever, the Packers won the title as a six seed, winning 31-25 off the back of three touchdown passes from the game's MVP, Aaron Rodgers.
The 1999 Rams heading into Week 1 were projected to finish as the worst team in football.
The undrafted rookie Kurt Warner was going to be the quarterback, and nobody expected the Rams - then coached by former Eagles coach Dick Vermeil - to have a winning record, much less make a playoff appearance and win the NFL Championship.
But Warner led the Rams to a 13-3 record in the regular season and then a 23-16 win over the Tennessee Titans in the NFL Championship.
That NFL Championship win was the start of something special in St. Louis.
Read more: NFL Championship date, location, history, how to watch and more
Perhaps the most unlikely NFL Championship winners would be the New York Giants in NFL Championship XLII.
At 10-6, the Giants had a good season, but nothing special. As for the AFC Champions, the New England Patriots were 16-0 in the regular season behind Tom Brady, Randy Moss, and Wes Welker.
The Patriots were trying to be just the second team in NFL history to go 16-0 and win the NFL Championship.
As 12-point favorites, many expected the Patriots to do just that. However, the 4th quarter featured one of the most memorable moments in NFL Championship history - 'The Helmet Catch'.
David Tyree made a one-handed catch with the ball pinned to his helmet on a crucial third down play that allowed New York’s drive to continue, and that turned into the game-winning touchdown drive.
The New York Giants completed one of the most iconic upsets in NFL Championship history with the 17-14 win.