Filipino superstar Manny Pacquiao needs only six rounds to beat Puerto Rican champion Miguel Cotto, according to revered boxing trainer Ignacio “Nacho” Beristain.

In a report by BoxingScene.com, Beristain said Cotto apparently lost his edge since receiving a brutal beating from Antonio Margarito last July.

"Cotto remained a little deteriorated after the fight that he had with Antonio Margarito and to be up against Manny Pacquiao, with all due respect - since I respect and I admire Puerto Rican boxing, but I believe that Pacquiao should put him on the canvas in five or six rounds," he said.

Beristain, who crafted Pacquiao nemesis Juan Manuel Marquez into a technical fighter, said Cotto had a hard time beating Joshua Clottey.

"In the fight against Clottey, you could see some of the aftermath of what happened with Margarito. Clotty is not a top-level fighter and nevertheless, in some moments Cotto was put in predicaments and the punches were affecting him," he said.

Top Rank promoter Bob Arum is arranging a November 14 bout between Pacquiao and Cotto at the MGM Grand in Las Vegas.

Beristain added that there are flaws in Cotto’s techniques that need correction. He said the Puerto Rican would be in trouble against Pacquiao if these errors are not addressed.

"Before, he was a fighter with good technique, fast and well cared for, but he doesn't seem like himself. He changed his coach, changed some of his habits and catches more punches. I do not believe that it would very advisable to take a fight like this after changing his main trainer."

“A fight with Pacquiao is a serious thing. You have to be well prepared. The fight with Pacquiao can be dangerous," he added.

Beristain was in Marquez’s corner when the Mexican champion fought Pacquiao to a controversial draw in May 2004. In March 2008, the Filipino won a split decision in his rematch with Marquez.

The veteran trainer also coached Oscar de la Hoya for the “Dream Match” with Pacquiao in December 2008. The Mexican-American, who won 10 titles in six weight classes, surrendered to the Filipino after eight rounds.