There was a moment at the end of Sunday’s tense AFC championship game when Peyton Manning seemed to be saying goodbye to his old self.

After the final whistle in the Denver Broncos’ 20-18 victory, Manning stood near the center of the field to greet Tom Brady in an exchange that was lengthy by the usual protocol for an ostensibly private moment played out entirely in public. Seconds later, Manning had a similar meeting with the New England Patriots’ coach, Bill Belichick.

There was a sense of farewell to each conversation. Manning even used the past tense when asked what he had said, answering that he told Brady and Belichick that it had been an honor to compete against them.

It was an interlude that might have summed up an epoch of NFL playoff football, a period that the 39-year-old Manning is about to leave behind.

Manning’s next game, fittingly in the 50th Super Bowl, will be contested in a new pro football era, and the proof of that will be found on the opposite sideline, where his counterpart on the Carolina Panthers will be the new-age quarterback Cam Newton.

When Manning entered the NFL in 1998, among his rivals at the position were Troy Aikman, Dan Marino and Steve Young. His current boss with Denver, John Elway, led the Broncos to back-to-back Super Bowl victories after the 1997 and 1998 seasons.

In what could easily be Manning’s last appearance in a weighty football game, he will take the field knowing that pro football is soon to leap forward with or without him. And that the next giant step might be taken by Newton on Feb. 7 at the Super Bowl in the form of his signature play, a daring, high-speed, quarterback sweep for a touchdown.

That is, unless Manning, through guile, painstaking planning and the art of a deft, veteran touch, can forestall the march of time for at least one more day.

The contrasts between the quarterbacks will be the main story line. On one side will be Manning, the old-style pocket passer and scion of a college and pro football icon. He plays for an established franchise, the Broncos, who played their first game in 1960. His athletic skills do not seem boundless, but instead appear to be football- or even quarterback-centric. If he has a known public image, it may come from his success as a television product pitchman — certainly not from demonstrative celebrations after touchdowns or first downs.

On the opposite sideline will be Newton, whose style of play is ever-evolving and transforming, like a startup tech company finding new ways to expand. Newton is a hybrid of abilities — pocket passer, scrambling improviser and halfback. He is big, strong and fast, and probably good enough to be a pro athlete in multiple sports. His team, the Panthers, is an NFL newbie by comparison, having played its first game 35 years after the Broncos made their debut.

And Newton may be known for his effusive celebrations after big plays and scores as much as for any of his considerable football accomplishments.

This will be Manning’s fourth Super Bowl appearance and Newton’s first. Manning carries the baggage of two previous Super Bowl losses, most notably the disaster of a 35-point defeat two years ago.

Newton brings with him the calm mind of the uninitiated. Time will tell if that is an advantage or a deficiency.

It is also the first Super Bowl matchup of two quarterbacks who were first overall picks in the NFL draft.

There are also story lines that do not involve the quarterbacks. Denver is still trying to reverse a sense of bad karma in the Super Bowl. The Broncos have lost five times in seven Super Bowl appearances, with every defeat by at least 17 points.

But Denver had the league’s stingiest defense in the regular season in terms of yards allowed (283.1 per game), and gave up just 18.5 points a game. The intrigue will be how the Broncos fare against the Panthers, who averaged 31.2 points and 366.9 yards in the regular season.

And Denver, which has a history of slow starts in Super Bowls, had better be on its game in the first quarter of the title game. Carolina has outscored the opposition, 55-7, in the first half during this postseason.

In an aside to New York Giants fans, Carolina’s ascent to the Super Bowl is also a reminder that the personnel mastermind of its success is Dave Gettleman, the general manager hired by the Panthers in 2013. For the previous 15 years, Gettleman had worked in the New York Giants front office, mostly as the pro personnel director. No organization can keep all of its talented people, but for the next two weeks — with the Giants desperately trying to rebuild an inferior roster — Gettleman, at least in New York, will be portrayed as the one who got away.

But in the end, the focus will be on the quarterbacks. The comparison is simply too appealing and absorbing. It is old versus young, venerable versus untested, circumspect versus flamboyant. It presages an interesting two weeks.

If only the game can live up to the billing.