By Grace Quinto (staff@latinospost.com) | First Posted: Sep 01, 2014 05:53 AM EDT

Freddie Roach is convinced that Manny Pacquiao will score a knockout win against Floyd Mayweather if the two boxing superstars eventually collide in a super fight next year.

In an interview with BoxingScene, Roach confidently said that Pacquiao will knock Mayweather out, saying that the reigning pound-for-pound king has lost a step based on his performance against Marcos Maidana in May.

Mayweather previously admitted that he looked slow during his first fight against Maidana, but he insisted that it was because he wanted to give the fans an exciting fight. But for Roach, Mayweather is just hiding the fact that his legs are already gone.

"I think Mayweather is shot, his legs are gone and Manny will knock him out," Roach said. "If he wants to get knocked out - sign the contract. He says he's sitting down [and not moving as often] to please the crowd. He doesn't care about pleasing no crowd, I don't think. He just can't move no more. His legs are shot. He's done."

Pacquiao is set to defend his World Boxing Organization welterweight title against Chris Algieri on Nov. 22 at the Venetian Resort in Macau, China.

If Pacquiao wins against Algieri, Roach is hoping that the Filipino boxing icon's next fight will be against Mayweather, conceding that the long-dreamed bout may not happen anymore if it will not be staged next year.

"I think this is it. I think if it doesn't happen after this fight - forget about it," Roach said.

The Hall of Fame trainer reiterated that they have done all necessary measures to show their willingness to face Mayweather, saying that they previously agreed to a 60-40 split.

"We've done everything possible on our side to make that fight happen, everything possible. We agreed to a 60-40 split at one time," Roach said.

Mayweather's demand for a random drug testing won't be an issue anymore since Pacquiao has been undergoing such test over his last several fights.

"All the fights have drug testing, and Manny is used to the drug testing, because at one time it was Manny who wouldn't do the drug testing in the beginning and that's why the fight didn't happen the first time around," Roach said. "But the thing is, since then Manny knows what the drug testing is, it doesn't affect him that much to take a little bit of blood out of him."

Top Rank Promotions CEO Bob Arum recently said in an interview with the San Francisco Chronicles that the fight could eventually happen in 2015.

However, it is still unknown at this point whether or not Mayweather is now willing to do business with his former promoter again. The unbeaten champion told Fighthype in December that he will not face Pacquiao as long he is under Arum's Top Rank Promotions.