Ray Mancini reached the peak of his boxing career when he knocked out Bobby Chacon on Jan. 1, 1984. He improved to 29-1, and it was his last successful title defense of the WBA lightweight title that he held for three years. He lost his next four fights, but his prime was strong enough for him to be inducted into the International Boxing Hall of Fame in June.

Floyd Mayweather Jr., who moved to 48-0 after beating Manny Pacquiao, is also well on his way to the Hall of Fame. But Mancini has some sharp criticism for the reigning welterweight champion.

"Mayweather thinks he’s the best ever but he’s delusional," Mancini said in a recent SportsGrid interview. "He says he’s better than [Muhammad] Ali which makes it hard to like him. He's not as smart as you think because a smart person wouldn't say that kind of stuff. If your name is mentioned in the same breath as Ali, [Sugar Ray] Robinson, [Sugar Ray] Leonard, you say, 'I'm honored,’ but he doesn’t say things like that. He doesn’t show humility."

But Mancini acknowledges Mayweather's skill.

"No one creates space for himself better than Floyd," Mancini said. "He uses his quickness to sharpshoot guys and then he gets out."

Mayweather has made a name for himself thanks to his flamboyant confidence. From his "The Money Team" entourage to his companionship with Justin Bieber to his appearance on "Dancing With The Stars," Mayweather has built a celebrity image. This publicity has overshadowed his patient defensive style in the ring and legal troubles such as domestic violence out of it.

Perhaps Mayweather was just playing a role, similar to the pro wrestling heel, to counter the declining interest in boxing. The past decade has been a challenge for the sport with a limited crop of stars outside of Mayweather and Pacquiao. This adds to Mancini's argument of Mayweather's inflated stature.

"Ray Leonard would still beat him," said Mancini, who is working an ambassador for the Fight Network, a television channel for mixed martial arts, boxing, kickboxing, wrestling and other combat sports. "Ray wanted to hurt you, he wanted to embarrass you. Ray wanted to close the show. This kid doesn't worry about that.

"Mayweather would lose if the competition was better. People ask me who is the best heavyweight boxer in world and I tell them he's playing in the NFL."

When comparing Mayweather to the all-time greats, Mancini makes a distinction between the eras before and after championship fights were shortened from 15 rounds to 12. That happened after Mancini's 14th-round KO of Duk Koo Kim in 1982. Kim died four days later from the brain trauma he sustained against Mancini.

"Floyd and Manny are the best fighters of the 12-round era," he says. "Of all-time? Top 30, maybe top 40. I can name 40 fighters I think had better careers than Mayweather. Kid Gavilán -- who is Kid Gavilán? He had 143 fights and was never knocked or stopped ever as a pro. A guy like Charlie Birdy, Ike Williams -- these guys fought during The Depression when you had to learn how to fight for survival, which made the competition much better than it is today. Henry Armstrong won three world titles simultaneously in 1938. In one year, three titles, three different weight classes, and almost won a fourth that year but judges scored it a draw. You’re telling me Floyd's greater than that? Hell no."

Mayweather has one fight left on his contract with Showtime, which is expected to be in September. At 38, Mayweather has been insistent that his 49th fight will be his last. For the moment, Mayweather says there will not be a rematch with Pacquaio.

Mancini will gain some respect for Mayweather if he picks the challenging opponent for the grand finale. Gennady Golovkin of Kazakhstan is also undefeated at 32-0 with his next fight coming against American Willie Monroe, Jr. at The Forum in Inglewood, Calif., this Saturday.

Golovkin, 33, is a middleweight, which has a 160-pound limit. Mayweather has been fighting at welterweight (147 pounds). Mancini believes the two can find a common ground at light middleweight (154). He also believes Golovkin, who Mancini says is the best fighter in the world, would end the Mayweather fairy tale.

"People ask me if Floyd would go up a class to fight Golovkin," Mancini says. "I tell them Mayweather wouldn't get within 100 yards of him. He won’t go in the same area code as Golovkin. Golovkin would destroy him. Floyd fought [Miguel] Cotto at 154, he fought Canelo [Saúl Álvarez]- at 154 -- Golovkin said he could make 154. Why wouldn't he fight Golovkin? Because Floyd Mayweather, Jr. doesn't have the balls. Golovkin would dismantle him."

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-- Follow Jeffrey Eisenband on Twitter @JeffEisenband.