Tony Ferguson respects Khabib Nurmagomedov as an athlete ... but says the 1 area he falls short is "mental toughness," and he's gonna expose that next weekend at UFC 223.
We spoke with the UFC interim lightweight champ in the lead-up to their long-awaited title fight ... and Tony told us Khabib's already shown his true colors by botching his weight cut days before they were scheduled to fight at UFC 209.
Ferguson says Nurmagomedov "took food off my kid's table" by getting that fight scrapped ... and he ain't letting that slide.
There's a lot more ... but to catch the full interview with "El Cucuy," you gotta tune into the "TMZ Sports" TV show tonight on FS1!