DENVER - Only one of them can be the greatest.
Peyton Manning could be the one - owner of a record four, working on five, Most Valuable Player awards, current holder of NFL single-season records for passing yardage and touchdowns and architect of a career-reviving second act, the likes of which has rarely been seen in any sport.
Tom Brady could also be that man - leader of five Super Bowl teams and winner of three titles, one-time holder of some of the records Manning holds now and author of an undefeated regular season. He also has that 10-4 record against Manning despite constant turnover on his roster and a lack of top receivers.
Manning and Brady will meet today for the 15th time, and the fourth time in the postseason, when the Broncos (14-3) face the Patriots (13-4) for the AFC title.
The winner between the top two quarterbacks over an era in which quarterbacks have never been so good will get what could be the last say in the debate over who goes down as the greatest - not so much because of what the win-loss numbers will say but because this could be the last time they meet with the stakes so high.
"I don't know that there will ever be another rivalry like it, or has been a rivalry like it," said John Elway, whose own rivalry with Dan Marino was held to only three meetings because of scheduling quirks over their decade-plus careers.
The game will either give Brady a chance to match Joe Montana and Terry Bradshaw for a fourth title or afford Manning the opportunity to win a second ring, which would put him one behind Brady, and in the same company with his brother, Eli, Roger Staubach and Elway, among others. It would also make Manning the first QB to win championships with two different teams.
While paying ultimate respect to each other - "I feel like he's been a better player each year than he was the year before," Manning said - neither quarterback professes to care much about how their own head-to-head showdowns.
But Brady has a .714 win percentage in the head-to-head meetings and also holds a 2-1 advantage in the playoffs partly because, more often than not, he's been surrounded by the more complete team.
He has been anything but a one-man show in New England this season, illustrated best by the fact that the Patriots are in the AFC title game even though Brady threw for 25 touchdowns - less than half of Manning's record-setting 55.