Indianapolis Colts came from 18 points down to beat the New England Patriots 38-34 and set up a Super Bowl showdown with the Chicago Bears.
It wasn't a panic situation
Indianapolis quarterback Peyton Manning
Quarterback Peyton Manning inspired the Colts' comeback from 21-3 down to clinch the AFC Championship game.
And the Bears beat New Orleans Saints 39-14 to win the NFC Championship.
Chicago, last in the Super Bowl in 1986, took a 16-0 lead and held off an inspired fightback from New Orleans before scoring three late touchdowns.
Manning, who threw for 349 yards and rushed for one touchdown, provided the leadership the Colts needed, as they racked up 32 points in the second half to clinch a famous victory.
"It's not the situation you want to be in, down 21-3, but we just took it one series at a time and everybody did his part and we came out with a great win," said Manning.
Manning completed the comeback with a seven-play, 80-yard drive which rookie Joseph Addai capped with a three-yard touchdown run.
With 60 seconds remaining, the Patriots tried to find a way back into the game but their quarterback Tom Brady threw an interception to Colts' Marlin Jackson.
"It wasn't a panic situation," added Manning.
"We knew we couldn't get it all back at once. We just slowly chipped away at their lead."
Urlacher's powerful performance helped the Bears to victory
"We haven't achieved the ultimate goal, but we have given ourselves the opportunity."
Meanwhile, New Orleans' defeat ended their fairytale season just short of their first ever Super Bowl.
The Bears' defence produced four turnovers and limited quarterback Drew Brees and the Saints' high-powered offence to 14 points.
With quarterback Rex Grossman struggling to get Chicago's offence in gear, linebacker Brian Urlacher and the Bears defence took charge.
They recovered two fumbles, leading to a pair of Robbie Gould field goals and a 6-0 lead early in the second quarter.
Another Gould field goal stretched the Bears' lead before running back Thomas Jones powered over from the two-yard line to put Chicago up 16-0.
With time running out in the half, the Saints hit back with a 73-yard drive, culminating in Brees hitting Marques Colston with a 13-yard touchdown pass.
The Saints exploded out of the blocks after the break, Brees finding Reggie Bush and the Heisman Trophy winner racing 88 yards for the touchdown to cut the deficit to 16-14.
It was a great team win for our franchise
Chicago linebacker Brian Urlacher
But the Bears defence was in no mood to let the Saints get the upper hand and recorded a two-point safety by forcing an under-pressure Brees to throw the ball away in his own end zone.
Back in control, the Bears put the game out of reach with a trio of fourth-quarter touchdowns, Grossman connecting with Bernard Berrian on a 33-yard touchdown pass and Jones and Cedric Benson also finding the end zone.
"We knew that the experts were criticising us all week long, so it's exciting for us," said Urlacher.
"It doesn't matter what anyone says. We knew what we had to do to win and we went out and did it.
"Our offence ran the ball, we stopped the ball, our special teams covered kicks like they did all year long, and it was a great team win for our franchise."
The two teams will meet at the Super Bowl in Miami on 4 February.