Tyson couldn't beat Buster Douglas once, so I don't see him beating Ali 9 times out of 10.
It's usually some snot nosed kid making a claim like that.
This is where we part ways my friend. Tyson w/ D'Amato in his corner never loses a bout to anyone, ever. D'Amato was the lynchpin that kept the Tyson mental machine going and when he died, King stepped in and ruined everything. Givens never happens with D'Amato in this corner, thus Tyson keeps his head in the game and never loses to Douglas. IMO - but I ain't wrong.
Ali could rope-a-dope all day long if he wanted while staying outside, but the second Tyson gets inside, it's all over. Touch jab right (or left), hard straight left jab for the setup (Tyson's best punch IMO). Finish with a hard right outside hook to the body. If it's there, take the upper. If not, do it again until he coughs blood. This is patented Tyson and he would have killed Ali's body. Can't raise your arms to punch without ribs. Ali fought during a time of punching fighters - he never face an inside brawler like Tyson. Only way Ali wins is by running circles for 10 rounds straight while occasionally landing something significant. IMO - Tyson eats Ali's babies alive and fvcks him till' he loves him.
Edit: Some would call Foreman an inside brawler I guess, but I'm not sure what in the hell Foreman actually was. He wasn't a brawler per se, more of a one-and-done Hulk Smash fighter. I've watched Foreman fights were he threw like 5 real punches the whole bout. Of course if just one of those makes 50% contact, it's Tweety Birds....but I digress...
Edit 2: I remember the Douglas fight like it was yesterday. My parents wouldn't order the PPV, so all I could watch was scrambled HBO feed while listening to the audio. It unscrambled for just a brief moment during Buster's entire knockout. It was insane at the time it happened. Nobody believed it was possible that Tyson could ever lose and we just sat there stunned.