by David P. Greisman

Brandon Rios believes that Manny Pacquiao’s one-punch knockout loss this past December to Juan Manuel Marquez clearly showed what Pacquiao’s weaknesses are.

“Right now, I'd say it's his chin. Let's see if he can take a great shot now,” Rios said Monday during a chat hosted on ESPN.com. “Another one is him coming in too much.”

Pacquiao delivered himself directly into the path of Marquez’s right hand. At a news conference on Tuesday, Pacquiao admitted that he had been too aggressive and too careless.

That loss was the second of two consecutive defeats for Pacquiao in 2012, the other coming in the form of a controversial split decision against Timothy Bradley.

“He hasn't looked like the Manny of old in his last two fights,” Rios said at one point in the chat. “But I can't worry about that. I know he's going to bring it for our fight just to prove to people that he isn't done yet.”

“My camp and I are getting ready for the best Manny ever,” Rios said at another point. “You can’t go off one KO, we're going off his body of work.”

Pacquiao, 34, is a former titleholder in eight divisions and a former lineal champion in four weight classes. His record is 54-5-2 with 38 knockouts.

Rios, 27, is coming off a decision loss this past March in a rematch with Mike Alvarado. The former 135- and 140-pound titleholder is now 31-1-1 with 23 knockouts.

Pacquiao-Rios will be contested in the welterweight division.

David P. Greisman is a member of the Boxing Writers Association of America. Follow David on Twitter @fightingwords2 or send questions/comments via email at fightingwords1@gmail.com