This year's Super Bowl will lift sibling rivalry to stratospheric levels as John Harbaugh coaches the Baltimore Ravens against a San Francisco 49ers team led by his younger brother Jim.
San Francisco pulled off the biggest-ever comeback in an NFC championship game, coming from 17-0 behind to beat the Atlanta Falcons 28-24 on Sunday, with Frank Gore running for a pair of second-half touchdowns.
The Baltimore Ravens also had to come from behind at half time as they beat the New England Patriots 28-13. Baltimore are back in the Super Bowl for the first time since 2001.
While there are plenty of interesting Super Bowl plot lines involving the players - from retiring Ravens great Ray Lewis to the sudden emergence of 49ers quarterback Colin Kaepernick - the sibling angle will make this coaching matchup the most scrutinised in the nearly half-century of Super Sundays.
The 49ers will be trying to join Pittsburgh as the only team with six Super Bowl championships, and trying to start a new era to build on the powerful 1980s and 1990s teams led by quarterbacks Joe Montana and Steve Young.
Sunday's victory came a year after San Francisco narrowly lost an overtime thriller to the New York Giants in the NFC decider.
The 49ers comeback set a new NFC mark. The previous biggest fight back was Atlanta's rally from 13 points down to beat Minnesota in 1999.
In the AFC, the record is 18 points, when Indianapolis rallied past New England in 2007.
Falcons quarterback Matt Ryan threw three touchdown passes in the first half. Passes of 20 and 46 yards to Julio Jones gave Atlanta the early buffer.
San Francisco responded, with Kaepernick throwing a 4-yard scoring pass to tight end Vernon Davis and LaMichael James breaking off a 15-yard touchdown run as the 49ers charged back.
Ryan made a 10-yard toss to Tony Gonzalez with 25 seconds remaining in the half, giving the Falcons a 24-14 lead at halftime.
The high-scoring pace of the first half continued as the 49ers began their run of points. Kaepernick had passes of 21 and 17 yards to Randy Moss in the drive. The 17-yarder moved the 49ers to the Falcons 5, setting up Gore's 5-yard scoring run which capped an 82-yard drive.
Gore then had a 9-yard run midway through the fourth quarter which completed the comeback. The second run came at the end of a short 38-yard drive set up by Ted Ginn Jr.'s 20-yard punt return.
"I take my hat off to Atlanta. They played hard. They've got a great team,'' Gore said. "But we fought, man. We fought and we deserved it.''
The top-seeded Falcons tried to pull out another season-saving drive at the end, but Ryan's fourth-down pass for Roddy White with 1:13 remaining was knocked down by San Francisco linebacker NaVorro Bowman.
Atlanta's defeat looked to have ended the career of Hall of Famer-to-be Tony Gonzalez, but Baltimore's linebacker Ray Lewis will take to the field one last time in the Super Bowl, in New Orleans.
Ravens' Joe Flacco threw three touchdown passes in the second half to get the better of opposing quarterback Tom Brady.
Flacco had two touchdown passes to Anquan Boldin and one to Dennis Pitta as the Ravens outscored the Patriots 21-0 in the second half.
Baltimore's defence made Brady look ordinary and stymied the league's top offence. Brady had been 67-0 at home when leading at half time.
New England suffered three injuries in the first half. Cornerback Aqib Talib hurt his thigh and defensive tackle Kyle Love injured his knee. Backup safety Patrick Chung was helped off the field after one play.
The Patriots also played without tight end Rob Gronkowski, who broke his left arm a week earlier.
Stephen Gostkowski had given the Patriots a 3-0 lead with a 31-yard field goal with 6:21 left in the first quarter. But the Ravens went ahead on Ray Rice's 2-yard touchdown run with 9:28 to go in the second.
Wes Welker then scored with just over 4 minutes remaining in the half on a 1-yard pass from Brady and the Patriots increased their lead on Gostkowski's 25-yard field goal on the final play before intermission.
Flacco's three touchdown passes came in just over 10 minutes in the second half and turned the contest on its head. He connected with Pitta with a 5-yard strike with 6:14 left in the third, then found Bolden for two TDs in the first four minutes of the fourth quarter - a 3-yarder and an 11-yarder.
The Ravens gained just 130 yards in the first half before Flacco guided them on scoring drives of 87 and 63 yards.