Floyd Mayweather against Manny Pacquiao is the fight that everyone wants to see.

Not just boxing fans, but sports fans across the globe want to see these two duke it out to see who the best Welterweight fighter of the 21st century really is.

Both Mayweather and Pacquiao have had Hall of Fame careers, but here are five reasons Pacquiao would defeat Mayweather if they ever fight:

1. Power

Mayweather may have the speed, but Pacquiao has the power. Pacquiao has 38 knockouts in his 57 career professional fights, whereas Mayweather has 26 knockouts in his 47 professional fights. Pacquiao's knockout rate is 11 percent higher than Mayweather's. Obviously, both of these great fighters have lost some punching power given the fact they are both past their prime, but the reality is Pacquiao hits harder. Spending all of 2014 facing Marcos Maidana twice won't help Mayweather get prepared for Pacquiao.

2. Southpaw

This fight has been in talks for about six years now, and we still haven't seen the two square off. One of the biggest reasons people think Mayweather refuses to sign the fight contract is because he is afraid of Pacquiao's fighting stance. Last year, promoter Bob Arum said, "I promoted the guy for 10 years, and I know how difficult it was to get him in the ring with any southpaw. When you talk about a southpaw who can move like Manny, that’s not the kind of opponent that Mayweather feels he would do well against.” Maybe it's true, or maybe it's just trash talk by Arum, Mayweather's former promoter. One thing is for sure: Mayweather isn't used to fighting left handed boxers, and facing Pacquiao would pose a huge threat with his different fighting style.

3. Energy

As previously stated, neither Mayweather or Pacquiao is in his prime, but Mayweather is the one who is closer to retirement. Mayweather will turn 38 years old next week, and he's two years older than Pacquiao. Mayweather doesn't have the same high endurance that he once had, and running around the ring avoiding the opponent for 12 rounds won't help against someone like Pacquiao. Chris Algieri isn't the greatest boxer in the world, but Pacquiao looked great in his last match against him, knocking Algieri down six times.

4. Preparation

Pacquiao wants this one badly. He and trainer Freddie Roach have been preparing for this fight for years in the event that Mayweather ever does fully agree to fight him. Facing Timothy Bradley and Algieri in 2014 was definitely a tougher task than scraping with Maidana twice. Not only does Pacquiao want to fight Mayweather -- and he has a terrific trainer in Roach -- but Mayweather's former promoter may even know a thing or two about his fighting techniques that could be very useful for Pacquiao.

5. Confidence

The biggest difference through this whole long ordeal has been desire. Pacquiao wants this fight. He's not afraid to lose. Mayweather, on the other hand, continues to change the contract and fight negotiations. This is the first time Mayweather believes he can actually lose a fight and thus lose his unblemished 47-0 record. Pacquiao isn't afraid to get in close and trade blows with his opponents, especially Mayweather. Let's not forget that Pacquiao was named the "Fighter of the Decade" for the 2000s.

Here are 5 reasons Mayweather will beat Pacquiao on May 2.

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