ENGLEWOOD, Colo. -- **No one saw this coming.
When Tom Brady stepped out of the locker room at spartan Foxboro Stadium on Sept. 30, 2001 for his first career start against Peyton Manning and the Indianapolis Colts, no one realized that the greatest head-to-head rivalry between two quarterbacks in NFL history was about to commence.
Seven days earlier, Brady was a backup, a sixth-round pick in 2000 who only took the field after longtime starter Drew Bledsoe suffered a sheared blood vessel in his chest and was hospitalized three days. Little was expected of Brady or the then 0-2 Patriots, losers of 19 of their last 26 games; the Colts were a double-digit favorite. A mismatch was expected.
See Peyton Manning break down the huddle and Kansas teammates Chris Harris Jr. and Aqib Talib prepare for the Patriots.
A mismatch is what happened, but hardly in the manner pundits foresaw. Brady managed the game and made no mistakes, and the Patriots pressured Manning into three interceptions, two of which they returned for touchdowns. New England romped, 44-13, and won 14 of 17 remaining games en route to a world championship, its first of three in four years.
Manning and the Colts struggled to a 6-10 season, but were soon back; it was the only losing season Manning endured as a starter since his rookie year, and the last time he missed the playoffs.
It was Chapter 1 -- 13 years ago -- an epoch in NFL terms. Elite teams rose, fell and rose again. The NFL regenerated itself. Manning and Brady pressed on, measuring themselves against each other, enthralling tens of millions.
"I grew up watching it," said cornerback Aqib Talib, who was 15 when Manning and Brady first dueled. "I grew up catching it on TV any time I could."
Defensive lineman Malik Jackson was 11 the first time Manning and Brady first met. He watched them "all the time."
"When those two came on, you knew it was going to be a good day," Jackson said. "Me being a defensive player, you're kind of skeptical for the defenses, but it's a great rivalry, and two great guys going at it.
"But luckily, there's defenses playing in the game, too."
And from the first meeting to the present, Belichick's defensive tactics created difficulty for Manning, whose career quarterback rating of 87.9 is 8.1 points lower in his duels with Brady than in all other games. His interception ratio is also higher: one every 30.0 passes in games against Brady-led teams compared to one every 38.4 passes in other situations.
"You could probably take an interview that I gave in 2003," said Manning, "but the answers are the same about the way they play. They create turnovers, they give you lots of different looks. They put pressure on offenses and then, of course, Tom's been there playing quarterback, playing at a high level so it's that double whammy, if you will."
It was a one-two punch that got the best of Manning six consecutive times from Brady's first start in 2001 through a 20-3 divisional-round loss at Gillette Stadium on Jan. 18, 2005. Since then, the series is more balancedl; Manning's teams have gone 5-4, including wins in two AFC Championship Games. But they've lost three straight in New England, and are 2-7 overall in Foxborough, with the last win on Nov. 5, 2006.
Manning's two wins at New England both came in his team's eighth game of that regular season. In Chapter 16, the Broncos will play their eighth game of the season. Any grand meaning to that will not be known until sometime around 8 p.m. EST Sunday.
During the last decade of near-equal terms, no series comes close to the buzz created by the quarterbacks. But with 90 other players in uniform for Sunday's game at Gillette Stadium, the successes and failures of other players could prove decisive.
Against the pass, these are two of the best in the game. New England's pass defense ranks seventh, allowing 6.9 yards per pass play. Denver's is second, at 6.3 yards.
Both defenses face daunting challenges against quarterbacks who are their usual surgical selves. Manning's average of 8.00 yards per pass play leads the league. But in the last four games, Brady has an 8.41-yard average per pass play, well above his 5.07-yard pace of September. The questions about Brady's future that arose after the last game of the Patriots' 2-2 start have vanished -- queries that drew Manning's scorn.
"It all depends on how much credit you give to quotes, sources, 'they,' 'people,'" Manning said. "I've always wanted to meet 'they,' and I've always wanted to meet sources because they seem to say a lot. I'm not speaking for Tom, but my guess is he didn't give 'they' or those people a lot of credibility."
The recent play of both quarterbacks, coupled with over a decade of excellence for each, turned Wednesday's interviews into an admiration society.
Said Patriots head coach Bill Belichick of Manning: He does everything well. He's the best quarterback I've coached against. He does it all."
Added Brady: "It's been a lot of fun. He's as good as anybody that's ever played."
Respect runs deep, and is reciprocated in kind. They know their place in history, from the unexpected rout of September 2001 to today. But they also know the story of their rivalry, which calls to mind epic, enduring sports duels like Nicklaus-Palmer and Bird-Magic, is unfinished.
"I've read where (Brady) wants to play until he's into his mid-40s and what not and he could probably do it," Manning said. "He keeps himself in great shape and he has great durability. It's credit to him."
And if Manning continues to play -- and push his peak ever higher -- the final chapters of his masterwork with Brady might be the finest of all. Not bad for a rivalry that seemed impossible to conceive when it began 13 years ago.