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Tom Brady and Peyton Manning is arguably the greatest quarterback rivalry in NFL history. Seemed fitting that Brady's first career NFL start was in Week 3 of that 2001 season against Manning and the Indianapolis Colts

The New England Patriots and Indianapolis Colts were division rivals for a year (Colts used to be in the AFC East), but ended up playing each other frequently thanks to division championships and deep playoff runs nearly every season. Brady and Manning squared off against each other 17 times, with Brady finishing 11-6 against Manning. 

Brady went 9-3 against Manning in the regular season while Manning went 3-2 against Brady in the postseason (Manning also played his final four years with the Denver Broncos). The two quarterbacks combined for nine Super Bowls and eight league MVP awards.

Why were Brady and Manning so good? As Manning admitted during Brady's number retirement speech, the pair actually worked out together in the offseason.

"I said, 'Tom, let's get together, go under the radar, don't tell anybody we're coming in.' Tom flies in on Mr. Kraft's plane," Manning said as the surprise guest at Brady's retirement celebration on Wednesday, via the Indianapolis Star. "We lifted weights together. We threw together with these high school receivers. We took their phones away. 

"We said, 'If you tell anybody that Tom Brady and I are working out together, and that we're friends, we're going to kill all of you.'"

Brady and Manning had a good laugh through the celebration, as the two quarterbacks reminisced about their playing days. Brady is No. 1 on the all-time passing touchdowns list (649), while Manning is third (539). Brady is also first in passing yards (89,214) while Manning is third (71,940). Brady is also first in fourth-quarter comebacks (46) while Manning is second (43). 

Both Brady and Manning have a long-standing friendship, even if it's one they didn't want the world to know about when they were playing. Of course, the quarterback battle wouldn't have been a "rivalry" either.