Francis Ngannou Says He's Best Heavyweight In MMA, Not Jon Jones

Jon Jones is NOT the most dangerous heavyweight MMA fighter in the world, despite dominating Stipe Miocic at UFC 309 ... according to Francis Ngannou, who says that distinction belongs to him!

TMZ Sports spoke with the former UFC heavyweight champ turned PFL MMA and boxing star following Bones return to the Octagon on Saturday at Madison Square Garden ... and we asked him, promotion aside, whether JJ was the best out there.

"You can't deny what [Jon] has done as a heavyweight," Ngannou said, "but I personally cannot classify him as the best heavyweight of all time. C'mon, man."

Of course, Ngannou and Jones were supposed to fight in the UFC, but the men could never reach an agreement ... and when Francis and Dana White's relationship fell apart, The Predator decided to pursue opportunities in the boxing world.

That meant Francis and Jon never shared the Octagon ... and therefore, there's no definitive answer. Unless you ask Ngannou.

"I claim the title," Francis said matter of factly.

And, despite the prospects of Jones and Ngannou sharing a cage seemingly being nonexistent, Ngannou isn't giving up on the idea.

"We both want this fight, for sure," Ngannou said, "It would be a good fight for us."

Crazier things have happened ... but if it does eventually go down, it won't be anytime soon.

Jon's under contract with the UFC ... and will almost certainly face interim HW champ Tom Aspinall or LHW champ Alex Pereira in the UFC sometime next year.