He already burned one NFL star in a sprint, but now Diddy's being called out by an ex-Super Bowl MVP ... who says there's NO DOUBT he's faster than the rap mogul -- and he's willing to bet on it!
The man with the confidence is Seahawks linebacker Malcolm Smith -- who famously picked off Peyton Manning for a TD in Seattle's rout of the Denver Broncos last year.
We told Smith about Diddy's recent victory over Tampa Bay Bucs safety Dashon Goldson in an uphill sprint ... and Malcolm told us there's ZERO CHANCE he'd be able to go 2-0.
"I'll beat Diddy. I'm willing to bet on that," Smith says ... "I'll bet Diddy everything."
Your move, Mr. Combs.