A rematch between Floyd Mayweather Jr. and Manny Pacquiao is very unlikely as of the moment, but trainer Freddie Roach believes that his fighter would be winning the second fight if it happens.  

The fight that happened last May, which was dubbed the "Fight of the Century" and was the highest-earning fight in history, ended with a unanimous decision victory for the unbeaten American. 

Roach believes that Pacquiao would have won the fight only if he was at a hundred percent. 

The former-eight division champion suffered a shoulder injury while training for the fight and it was aggravated during the bout against Mayweather which limited his movements according to his camp. 

Five days after the bout, Pacquiao went through surgery and is currently recovering very well, according to reports. 

Top Rank CEO Bob Arum said that his prized slugger will not fight this 2015, but he will be back in the ring early in 2016. 

A potential opponent for the Filipino is British top contender Amir Khan, but a rematch against Mayweather will always be an option. 

If it happens, Roach sees a different outcome as he told Boxing News, "Manny would do much better in a rematch, if the shoulder gets better. We were doing well until the shoulder went in the fourth round and we had a tough time after that. I do think we can beat Mayweather, 100 per cent."

Roach also said Mayweather will not be retiring after his 49th fight and will likely have one more.  

Mayweather said after the Pacquiao fight that he would be fighting for the last time this September. A few weeks ago, he chose Andre Berto among other contenders to be his potential final career opponent. 

The fight will be on Sept. 12 at the MGM Grand in Las Vegas and if Mayweather wins, he would be tying the legendary Rocky Marciano's 49–0 record.