The 23-year-old called out Conor after destroying Nate Robinson on the Mike Tyson undercard over the weekend -- and while many scoffed at Jake's comments, Paul tells TMZ Sports he's dead serious.

"My team is talking to his manager but that's all I'll say," Jake said with a smirk.

Then came the smack talk ...

"No other fighter with this big of a platform is calling out McGregor. My dogs have more followers than the guy he's fighting in January."

That's not exactly true ... Conor's next opponent is Dustin Poirier, a widely respected UFC fighter with 1.7 million followers on Instagram.

Jake's dogs, Lil Moo and Thor, have 1.6 million followers.

Jake has 13.9 million.

Paul says it's not a matter of "if" when it comes to Conor, it's a matter of "when" -- claiming, "It's gonna be legendary."

"I'm gonna win, too! That's what I want people to understand!"

Jake added, "I'm gonna dedicate my life to winning that fight because I'm not going in there just to say I did it -- I'm going in there to f**k Conor McGregor up."

There's more ... Jake also tells us he's reached out to Nate Robinson after the knockout and hopes to connect with him in the future.