Shocking admission from Tyreek Hill ... the Kansas City Chiefs All-Pro says he would flat-out LOSE in a race against Lamar Jackson!!!

The wide receiver made the revelation to TMZ Sports this week ... saying the Baltimore Ravens QB is just that damn fast!!!

"I done retired from racing, man," Hill says. "So, he'll probably get me right now."

Incredible level of respect for the QB from Hill ... considering most in the NFL believe Tyreek is the fastest player BY FAR.