Reigning pound-for-pound king Floyd Mayweather Jr.'s upcoming fight with Andre Berto will be more challenging compared to his previous bout against Manny Pacquiao, according to former light middleweight champion Austin Trout.

For "No Doubt," fans should not underestimate Berto's skills because he deems him as a tougher opponent for Mayweather than "Pacman."

But can Berto actually pose a threat to Mayweather's aim of matching Rocky Marciano's win-loss record of 49-0? The former light middleweight champion thinks it's a possibility.

"To be honest, Berto might give him a better fight than Pacquiao because Pacquiao looked gun shy, he didn't want to fight, he looked like he didn't want to be there. Mayweather's fought all the names in the game - not necessarily in their prime, but definitely fought all the names in the name. Berto is the fight that's gonna happen," Trout told OnTheRopesBoxing.

Trout is clearly not impressed with the performance of the former eight division champion and he thinks "Pacman" will only choose to clash with a "safe" opponent next year.

Meanwhile, another boxer acknowledged Berto's boxing style and attitude. Former International Boxing Federation junior middleweight king Ishe Smith believes Berto is not like "Pacman" who would just give an "excuse" if he loses.

"Berto won't have excuses. He will come to fight and he's never been in a dull fight. He's [Berto] got a pretty good name in the sport. Everybody knows who he is. I think he's going to fight hard. I think he's going to put up a better effort than Manny, but I don't think it's going to be enough," Smith told FightHype.

A lot of boxing fans were disappointed with the outcome of Mayweather's fight against Pacquiao in May. As in any fight, varying opinions on why "Pacman" lost were raised. The Philippine champ's fans didn't approve of Mayweather's performance in the ring, as they claimed that the fighter only "ran and hugged" Pacquiao during the fight. On the other hand, Pacquiao was only able to do so much as he was suffering from an injury, which was only revealed after the match.

It would have been different if Pacquiao was physically ready to clash with Mayweather and sadly, he may not be able to avenge himself against Mayweather since the unbeaten champion has already announced that the September bout will be the final fight of his career, unless of course, if he changes his mind.

Thus, whether Berto likes it or not, all eyes will be on him on September 12, at the MGM Grand Las Vegas.