Cotto is defending his WBA (super) light middleweight title against Mayweather in the biggest fight so far this year.
Cotto is the underdog and could benefit significantly from a win. If he is the one to end Mayweather's undefeated streak he would forever be cemented in boxing history.
Here's a look at everything fans need to know about the fight, including other things they should look for.
Where: MGM Grand Garden Arena in Las Vegas, Nev.
When: Saturday, May 5 at 9 p.m. ET
Important Things to Follow
Mayweather's defense is a big reason for him coming into this fight still undefeated. He has allowed his opponents to be the aggressor and he reacts when he gets his opportunities.
Cotto has improved his defense over the last few years and could try to beat Mayweather at his own game. He has moved away from just trying to swing until his opponent is not standing. Cotto could take the first few rounds as a chess match and then look to explode in the later rounds.
Cotto could also try to push the pace a little and pressure Mayweather. He could try and work the body, which is a dangerous approach because of Mayweather's speed.
Something that could play a factor in this fight is the focus of Mayweather. Along with his fight with Cotto, Mayweather could have Manny Pacquiao and jail on his mind.
Mayweather has to serve a jail sentence shortly after his fight. That has to be in the back of his mind and could play a role in this fight.
Is Pacquiao Next?
The fight that everyone wants to see but may never, could be the next challenge for Mayweather.
Mayweather has made it known that he doesn't intend to stop fighting anytime soon. That leaves the dreams for the "Fight of the Century" open.
A win over Cotto would help cement Mayweather as the best pound-for-pound fighter in the sport and add another win to his legendary career. However, their will be a gaping hole in his career, if he doesn't fight Pacquiao.
There is not much more for Mayweather to do and after he serves his jail sentence, the next fight could be against Pacquiao.