Manny Pacquiao had the backing of the vast majority of the record-breaking amount of people who tuned in to see his fight vs. Floyd Mayweather Jr., but all the positive energy in the world couldn't maneuver him past Mayweather's superior reach. Pacquiao looked like a 36-year-old man vs. Mayweather, who despite being older was quicker and fresher.

Pacquiao was able to tag Mayweather twice with his patented straight left hand, but all he could do was momentarily wobble the pound-for-pound king. In the past those shots might've been enough to knock him out. Even if he lost the biggest fight of his career, Pacquiao remains a boxing icon and will likely continue to fight. If he does, here are the top three opponents he could face.

Danny Garcia (30-0-0, 17 KO)

Garcia has nothing left to prove at junior welterweight, and is struggling to make the weight. If he moves up to 147 pounds, a big money fight vs. Pacquiao would be quite the introduction to the weight class. Stylistically, the fight makes sense. Garcia tends to wait and counter punch, while Pacquiao is constantly hopping forward. Pacquiao's seen some of his power diminish, but he might seem strong against Garcia, who is coming up a weight class.

It's likely Garcia would prefer to take a less dangerous opponent in his first fight at 147 pounds, but if he wants to make big money Pacquiao is logical.

Terence Crawford (26-0-0, 18 KO)

Crawford is one of boxing's greatest young talents, a smart fighter armed with good power, defensive chops, and the ability to fight in a conventional or southpaw stance. He recently moved into the junior welterweight division and impressively stopped Thomas Dulorme in the sixth round; Dulorme had once been a top prospect. Pacquiao might be considering a drop in weight class after losing to Mayweather. He hasn't knocked anyone out in six years, and he may need to fight smaller fighters in order to become electrifying once again. Pacquiao may be too severe a test for Crawford at this stage of his career, but it'd certainly be worth his while financially.

Juan Manuel Marquez (56-7-1, 40 KO)

Who knows how much Pacquiao, 36, or Marquez, 41, have left in the tank. Both fighters may have already fought their last fight. If Pacquiao and Marquez are coming back though, one last ride may be the ideal send-off for both, since neither has anything left to prove in this sport. Marquez has said he is content to close their four-fight rivalry with his emphatic 2012 knockout, since he considered it just desserts for the previous "robberies" he'd suffered in his previous three bouts. Very few pairings in boxing have been as magical as Pacquiao-Marquez though, and a fifth bout serving as both men's swan song would be the perfect way for both warriors to go out.