By Lou Aguila (staff@latinospost.com) | First Posted: May 12, 2013 02:01 PM EDT

Brandon Rios, who's set to fight Manny Pacquiao in Macau this coming November, believes nobody can beat Floyd Mayweather inside the ring, even though the American boxer has already passed his prime.

The 27-year old Rios admitted he's really impressed by another showcase of boxing prowess from Mayweather, who cruised to a unanimous decision victory over a much a bigger Robert Guerrero on May 4.

"Floyd's still unbelievable," Rios told Boxingscene.com. He's untouchable. I don't think nobody can beat that guy. He's just too good."

Rios added that it's not hard to imagine Mayweather finishing his career without a loss, given his unique ability to defend and launch counter attacks with ease.

"I don't know," Rios said of Mayweather's technical boxing skills, according to Boxingscene. He was born as a fighter. Floyd's just [expletive]. That's all I can say."

Evaluating the performance of Floyd's challenger, the hard-hitting Texan thinks Guerrero was too passive in the fight and often caught napping by Mayweather's quick jabs and punch combinations.

"Honestly, I thought Robert Guerrero was going to come out and be more aggressive," Rios said. "At least he could have said he got knocked out by the best. I thought he was going to be a little more aggressive.

Yet, Rios didn't blame Guerrero for the loop-sided outcome, insisting that's really hard to beat a boxer possessing the same quickness and agility like Mayweather.

"But it's frustration," Rios continued. "When you get frustrated, your mind doesn't see the same or concentrate the same. You don't do the same punches that you planned. When you get frustrated, you're [expletive], pretty much."

Rios, who holds an impressive record of 31 wins, 23 KOs with one loss and a draw, is fresh from a unanimous decision loss to Mike Alvarado last March 30.

However, he's in for the most lucrative fight of his career when he faces Pacquiao on November 24 in Macau, China.

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