Jamal Lewis played with a bunch of legends on the Ravens ... but says Peyton Manning -- his 1-year teammate at Tennessee -- was the guy who showed him how to be a pro.

The ex-NFL star told us he went full Allen Iverson when he showed up at UT, not giving a damn about practice ... and it almost got him benched.

Then, 1 practice sesh with Peyton changed everything.

"Every single play was just like he was in the game ... full tilt," Lewis told TMZ Sports. "That's a trait that I adopted and I took on, and it helped me get to where I am."

FYI, Jamal helped Baltimore win a Super Bowl as a rookie, and threatened Eric Dickerson's all-time single-season rushing record a few years later.