Mayweather vs. Pacquiao 2015 Dream Fight Sparks Tweet from Muhammad Ali

Leading up to his epic showdown on May 2 against Manny Pacquiao, the undefeated Floyd Mayweather Jr. has made a point to tell everyone who will listen that he's a greater boxer than legends like Muhammad Ali and Sugar Ray Robinson. 

During an interview with Stephen A. Smith of ESPN (h/t Austin Knoblauch of the Los Angeles Times), Mayweather tried to convince viewers he's better than Ali because he's fought opponents in different weight classes:

"

[Ali] only fought in one weight class...No one can ever brainwash me to make me believe that Sugar Ray Robinson and Muhammad Ali was better than me. But one thing I will [say]: I'm going to take my hat off to those guys and respect those guys because those are the guys that paved the way for me.

"

Ali wasn't going to stay quiet for long. The legendary boxer took to Twitter to deliver a not-so-subtle jab at Mayweather about his claims:

Ali's tweet was also directed at George Foreman, who was 40-0 when Ali defeated him in 1974 and told TMZ Sports that Mayweather is "pound-for-pound" better than either of the legendary heavyweights. 

Even at the age of 73, Ali isn't going to let any fighter claim he's a superior boxer.