AFC Championship, 1971: Miami 21 Baltimore 0

Game information
The Dolphins reached the AFC title game in their sixth season, thus becoming the first of the then-four NFL teams which had commenced play after the start of the Super Bowl era to play in a title game. This made them the youngest franchise to make it to a Super Bowl era title game up to that point. Miami won the AFC East with a 10–3–1 regular season record and defeated the AFC Central champion Kansas City Chiefs in the longest NFL game in history, (27–24 in double overtime) at Kansas City's Municipal Stadium in the Divisional Round to advance to the AFC Championship game.

This was the second consecutive AFC Championship Game contested by the Colts, their third title game in the past four seasons, and their sixth title game appearance overall. While the defending AFC and Super Bowl champions failed to repeat as AFC East champions, their 10–4 regular season record was good enough for the then-one AFC wild card berth. Baltimore defeated the AFC Central champion Cleveland Browns 20–3 at Cleveland Stadium in the Divisional Round to reach the AFC title game.

In addition to being the first playoff meeting between these teams, the AFC title game was the Dolphins' first playoff game at home. Their only previous playoff game had been in the 1970–71 NFL playoffs when they were the AFC wild card. Just as significantly, it pitted Dolphins coach Don Shula against his former team, which he had left for Miami in acrimonious circumstances prior to the 1970 season.

This was the first post-merger conference championship game contested between division rivals, and also the first in either conference to not feature a West Division team. Miami and Baltimore split their two regular season games in the 1971 season, with the Dolphins winning 17–14 at the Orange Bowl while the Colts won 14–3 at Memorial Stadium.

Although Miami quarterback Bob Griese completed only 4 passes, the Dolphins defense shut out the Colts. Defensive back Dick Anderson intercepted Johnny Unitas three times, returning one of them 62 yards for a touchdown.

Paul Warfield recorded a 75-yard touchdown reception midway through the first quarter on the Dolphins second drive. Meanwhile, the Colts managed to move the ball close enough for Jim O'Brien to twice attempt field goals, but he missed both times. In the second quarter, the Colts drove from their own 18 to the Dolphins 9-yard line, featuring a 28-yard reception by Don Nottingham, but on 4th down and 1, Nottingham was stuffed by a gang of Dolphins defenders just inches short of the first down marker.

In the third quarter, Unitas threw a pass that was deflected by cornerback Curtis Johnson into the hands of Anderson, who took off for a 62-yard scoring return. Then in the fourth quarter, Griese's 50-yard pass to Warfield set up Larry Csonka's 5-yard touchdown run.

This was the first postseason meeting between the Colts and Dolphins.

The AFC champion Dolphins made their first Super Bowl appearance. Miami lost 24–3 to the Dallas Cowboys of the National Football Conference in Super Bowl VI.

This was the first of three consecutive AFC titles for the Dolphins, who would go on to win two consecutive Super Bowls with their first such championship being the only perfect NFL season in the modern era.

This was the last AFC Championship Game appearance by the Colts while they were based in Baltimore. The Colts relocated to Indianapolis in 1984, but did not return to the AFC Championship Game until the 1995 season which incidentally was the last season of the NFL's absence from Baltimore. A Baltimore-based team would finally return to the AFC Championship Game in 2000, which Baltimore's current team (the Ravens) won en route to their first Super Bowl championship.

Six NFL teams have been enfranchised since 1971, four of which reached a title game (two in each conference) in less than the six seasons it took Miami to do so. Of those four clubs, the only team to win their first title game was the aforementioned Ravens in their fifth season. The Ravens, upon their enfranchisement, acquired the roster of the Cleveland Browns, who suspended operations for three seasons. The Ravens were not a 1996 expansion team from a football operations perspective.

Wikipedia