Boxing fans are eagerly awaiting Floyd Mayweather Jr.’s decision on whom he will fight next, because it will set the remainder of the year’s dominos in motion. As of now, the leading candidates to share a ring with Mayweather on May 2 are Manny Pacquiao, Miguel Cotto, and Amir Khan.

Money-wise, there is no fight bigger than Mayweather-Pacquiao. There are a lot of obstacles that have prevented fans from seeing that fight happen though, and some of them are cropping up during the most recent talks. But viewing these fighters strictly inside the ring, who presents the toughest challenge for the undefeated Mayweather?

Amir Khan (30-3-0, 19 KO)
Khan is the youngest of the three possibilities, and has the quickest hands (sorry Pacquiao fans). He just recently moved to welterweight and has only two fights under his belt at 147 pounds—dominant victories over Luis Collazo and Devon Alexander.

Khan is technically sound, adept at throwing high-volume combinations with accuracy, and is comfortable going the distance.

He has had a tendency to get suckered into slugfests, which have led to two knockout losses and other knockdowns. Those missteps have put a blemish on his resume, and have been referenced by Mayweather himself as signs he doesn’t deserve such a big fight.

Under the tutelage of new trainer Virgil Hunter though, Khan has adjusted his approach. He fights more cautiously, holding when he may be in trouble. He has maintained his blazing speed though, and simply added more ring intelligence to his repertoire. He took Collazo’s punches, but questions about his chin will likely follow him until he faces a big puncher and eats some shots.

Miguel Cotto (39-4-0, 32 KO)
Cotto is the WBC middleweight champion, but his title was won at a a159-pound catch weight. He is small for the division and should have no trouble getting back to 154 pounds for a Mayweather rematch.

Cotto is the largest of these three opponents; while Mayweather clearly doesn’t fear bigger, more powerful opponents, none of Mayweather’s larger foes possess Cotto’s skill.

Since hooking up with Freddie Roach, Cotto’s feared body punching has been revitalized, an aspect of his game that was absent from their 2012 bout which left Mayweather with a bloody nose.

Against Sergio Martinez Cotto’s footwork was immaculate. He cut off the ring from Martinez, peppered him with shots upstairs and downstairs, and stung him with those shots.

Cotto has the tools to keep pressure on Mayweather, who at 38 years old may not be able to avoid accurate punches quite as well as he did several years ago. Cotto also doesn’t fight as recklessly as power punchers like Marcos Maidana do. He is a future Hall of Famer fighting as well as he did in his prime.

He is not likely to throw his game plan out the window if Mayweather’s on his game defensively at the outset, and he won’t be wild like Maidana was. Cotto’s game is control, although he may not have the volume to overwhelm Mayweather’s senses like Maidana did early in their first bout.

Manny Pacquiao (57-5-2, 38 KO)
Pacquiao’s offense is the most difficult to prepare for of these three opponents, and even though he hasn’t scored a knockout win since 2009, his whirling dervish style is unlike any other fighter in the sport.

Since a hotly contested loss to Timothy Bradley and a knockout loss to Juan Manuel Marquez Pacquiao has bounced back with three utterly dominant performances. Pacquiao was fast, and showed power against Chris Algieri in his last bout, scoring six knockdowns en route to a unanimous decision victory.

Of these three opponents Pacquiao is the most decorated, and he has beaten several common opponents with Mayweather in more severe fashion (Ricky Hatton, Cotto, Oscar De La Hoya). Pacquiao’s power has waned in recent years though, with trainer Freddie Roach thinking a move down to junior welterweight is the remedy.

Mayweather isn’t likely to fear Pacquiao’s power much having withstood clean shots from the likes of Maidana last year. Pacquiao’s unorthodox offense is unlike anything Floyd has seen before though, so the how the styles clash would be intriguing.

Verdict: Khan is the fastest of the bunch, and Pacquiao the trickiest, but Cotto presents the greatest overall challenge. He is the only one with experience vs. Mayweather, and has the best chance of keeping Mayweather where he wants him.

Cotto’s focus on body punching may be able to wear down an aging Mayweather, and his power is the greatest of the three.

Pacquiao’s style is at times too reckless, and looks tailor-made for Floyd, whose jabs and quick counters will be there all night if Pacquiao isn’t careful. Khan has quality wins on his resume, but he’s never faced anyone near Mayweather’s caliber. He has fast hands, but that questionable chin could be victimized by Mayweather, whose power is underrated.

The toughest fight for Mayweather is Cotto, provided the middleweight champ isn’t forced to cut down to 147 pounds.