By Nate Dunlevy
Cold, Hard Football Facts peytonologist
Asante Samuel sprinted toward the end zone with Peyton Manning’s errant pass in his hands. The groan and then silence from 60,000 stunned Hoosiers must have been music to his ears. The Patriots now led 21-3 in Indianapolis and stood just over two quarters from another victory in the AFC title game, their third in four years at the expense of the weak-kneed Colts.
Surely, New England would go on to beat its NFC opponent in the Super Bowl for the fourth time in six years and be remembered as one of the singular dynasties in NFL history. The Colts would be remembered only for being not good enough, a glitzy, entertaining team that never had the fortitude to win in the playoffs.  
The Colts and Patriots have played some of the most exciting games of the past 10 years. The Patriots won a 38-34 thriller in Indianapolis in 2003, famous stopping the Colts on the goal line with just seconds remaining. 
A missed field goal at the gun gave the Patriots a 27-24 win in Foxboro the following season. In 2007, the two teams met undefeated in Indianapolis, and the Patriots staged a furious rally to win 24-20 and save their 16-0 season. Last year, Belichick elected not to punt deep in his own territory as the Colts stormed back to stun New England, 35-34, in what's remembered as 4th-and-2-Gate.
While Colts-Pats games tend to be thrilling, they are almost always significant as well. The winner of the Colts Patriots regular season game has gone on to represent the AFC in the Super Bowl five of the past seven seasons.
Of all the fantastic finishes and crucial wins, no game has affected the direction of the rivalry as much as the Colts 38-34 win in the 2006 AFC Championship game.
After throwing an interception to Samuel, Manning was unable to move the Colts in their ensuing drive. He was sacked twice. He was called for a delay of game penalty. Finally, a desperation heavy to Marvin Harrison bounced of his favorite receiver's hands. The Colts were dead. There was no reason to expect a comeback. By half time, Indy had managed just two field goals and trailed 21-6.
As the Cold, Hard Football Facts noted at the time, the gravediggers of the gridiron were ready to dump dirt on the legacy of Manning: a guy who just couldn't get it done in crunch time.
But Manning came out of the break smoking, tearing apart a vaunted New England defense that collapses after half time. Over the span of two drives, he completed 6 of 8 passes, rushing for one touchdown and throwing for another. After he hit Marvin Harrison for a two-point conversion, the score was suddenly tied. 
With 3:30 to play in the second quarter, the Patriots had the ball and an 18 point lead.  By the 4:06 mark of the third quarter, the lead had been completely erased. The blowout turned into a back and forth affair. 
It was Peyton Manning's finest hour.
To their credit, the Patriots didn't blink. They posted three scoring drives in the second half, but put up only one touchdown. Before the 2006 season, Belichick drew a hard line with Super Bowl hero Deion Branch, trading him to the Seahawks rather than granting him a new contract. 
As the AFC Championship morphed from route to shootout, the Patriots struggled to find the end zone.  Reche Caldwell had a brutal second half and dropped multiple passes. Despite everything, New England still had a chance to ice the game.  With 2:30 to play, and Indy down to a single timeout, a third and five was all that separated the Pats from the promised land.  Tom Brady threw to the inside of aging vet Troy Brown who was leaning to the outside.  Bob Sanders knifed in to break up the pass.  The Colts had new life.
80 yards.  Everything he had worked so hard for his whole life was 80 yards away.  Peyton Manning broke the huddle with the Colts, fortunate just have the ball back after a disastrous three and out just minutes earlier.  His hand was throbbing, and hopes of an entire city was resting in it.  He always denied there was a monkey on his back, but at that moment an 800 pound gorilla named the New England Patriots was staring back at him across the line of scrimmage.
A score was no given for the Colts. The fourth quarter had been ragged. Their only touchdown game on a fumble recovery in the end zone by center eff Saturday. Manning had whacked his throwing hand against a helmet earlier in the quarter and gripping the ball was an issue. Trailing 34-31 on their own 20, the Colts drove to the Patriot 11 yard in just 24 seconds. Two runs moved the ball to the three yard line, and the fate of two franchises hung on a third down call.
They had been here before. If the Colts could have scored against the Pats in 2003 at home, the AFC championship game would have been played in Indianapolis that year. Perhaps the next three years of NFL history would have been rewritten. Now, both teams stared each other down again.
The Patriots had always come up with the big play, the key stop. Manning had never figured out the right play to dial up. This was the order of things in the NFL. 
In the Colts huddle, Marvin Harrison said, "Let's run it!" If even Harrison wanted to run the ball, no one was going to argue. Behind a devastating block by Saturday, rookie Joseph Addai darted into the end zone untouched.  The sound of the crowd was the sound of the old order of things collapsing and giving way to a new reality.
Peyton Manning, the same Peyton Manning who Belichick had frustrated in playoffs past, had led Indianapolis to the Super Bowl. The Patriots were left to pick up the pieces, wondering where it all went wrong.
It was and remains the greatest and most improbable comeback in conference title game history. Manning and the Colts were on the verge of being routed at one point. But they stormed back to steal control of the game and even their own legacy.
The relationship between the two teams has never been the same. Up through the Samuel interception, the Patriots had dominated Manning and the Colts. After that crossroads moment, the Colts and Manning have dominated the Patriots and defensive whiz coach Bill Belichick.
Manning vs Belichick Before and After the Samuel Return
The game was a crossroads for New England. Having watched his aging defense melt in the heat of a charged up RCA Dome, Belichick could have gone about rebuilding his signature unit. 
Instead, he repented of his previous decision to ship Branch out and restocked the Patriots offense. Belichick had lost three consecutive games to Peyton Manning, and could no longer be sure he had any answers for him. If the Patriots hoped to topple the Colts, they would have to pile up points faster than Indy could.
In an effort to give Tom Brady the weapons he had never before had, the Patriots swung two key transactions, brining in Randy Moss and Wes Welker to revitalize the passing attack that failed to pick up the last first down necessary to make the Super Bowl. 
The result was electric. The 2007 Patriots fielded the highest scoring offense in history. They also fielded an aging defense, as Belichick chose to go with veterans over youth.
But New England has been struggling to rebuild tits defense ever since. Statistically, they had sound seasons in 2008 and 2009, but back to back beat downs last season by Manning and Drew Brees exposed the New England secondary as fraudulent.  The 2009 season ended with an unthinkable blow out loss to Baltimore in New England. 
After the 38-34 loss to the Colts in the 2006 AFC title game, the Patriots had a choice. They chose offense. Was it the right choice? Well, the Cold, Hard Football Facts say no.
The Patriots were 12-1 in the postseason in the Tom Brady Era before losing to the Colts. Since that game, they've gone just 2-2. They had won three Super Bowls in the five years before that game. They've won zero Super Bowls in the three years since.
For Manning, the game was a crossroads as well. The Colts won the Super Bowl two weeks later. Manning has since won two more MVP awards, taken the Colts back to another Super Bowl, and cemented his legacy as one of the greatest players in NFL history. 
Now, less than four years after coming to New England, Moss is gone. The Patriots field one of the youngest defenses in the league with only two players over 30 getting significant snaps. They've played the last four games against the Colts in Indianapolis, winning only once. On Sunday, the game returns to Foxboro.
The Colts have been relentless, winning nearly every week for the past three seasons, but injuries and age have led some to suspect that they are vulnerable, that their invisible window is closing.
Regardless, Indianapolis-New England games are more than just great games. They define seasons and they've defined this era in football history. They are the pass key to the Super Bowl in the AFC. 
In a tight playoff race, both teams need a win Sunday.  Should they meet in the playoffs, the game will almost assuredly be played in the winner's stadium.
Two teams at a crossroads. The winner may well be going to the Super Bowl ... again.
Cold, Hard Football Facts contributor Nate Dunlevy publishes the Colts blog, He's the author of "Blue Blood: Tales of Glory of the Indianapolis Colts"