"It's hard, very, very hard. Coming from somewhere where boxing has been my whole life, I've been doing this for 30 years. You look back you see a young kid, a 20 year old kid, not thinking much, doing fights here and there, then becoming world champion and becoming a legend among the sport is something that's not easy to leave," Barrera told Sky Sports.

"It's not easy to come to terms with but it's something everybody has to do eventually."

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For him taking part in exhibitions, like the one he will have with Ricky Hatton on November 12 on Sky Sports, is part of transitioning out of boxing entirely. He views it more as a celebration.

"Marco Barrera against Ricky Hatton is something that people would dream to see back in the day," he said.

"I think the people at the exhibition are going to be in awe, they're going to witness something incredible, they're going to witness two fighters - out of their prime - but still doing what they've been doing their whole life. I don't want people to get mixed up.

"This is not a real fight. There's not going to be blood. There's not going to be those heated moments. In an odd way we're going to make our friendship with Ricky Hatton stronger by exchanging some punches and hugging each other.

"Doing an exhibition is less worrying, there are less things involved. It's a little bit more calming knowing that there's not much on the line.

"We'll make sure to have fun and give people a good show."

He has noticed how hard Hatton is training for their exhibition though.

"Ricky and I are really good friends. We are two boxing legends so we know what comes with being in the ring. We know the respect. However I got a little bit shocked seeing Ricky post all his progress, post all his workout routines, his boxing, I can see he's getting in great shape," the 48-year-old said.

"I'm training hard as well. It's going to be a good exhibition, it's going to be a good fight for the people."

While Hatton is a friend, it was boxing another Briton that gave Barrera his most satisfying victory.

"My biggest rival has definitely been Naseem Hamed," he revealed. "It was not only my biggest fight, it was the little push that I needed for not only Mexico, not only the United States but for the whole world to look at Marco Antonio Barrera as the fighter that he was.

"The biggest one, I consider that my best fight."

His trilogy with countryman Morales in boxing is the stuff of legend. "Regardless of where you come from, regardless of how your training was, regardless of preparation, when you're in the ring with a Mexican you know that fight will be great," Barrera said.

"The Mexican fighter's definitely stubborn. The Mexican fighter likes the exchange of punches. They just like giving a spectacle, it doesn't matter if they win or lose. They go in there for the win. They fight their heart out. It doesn't matter what, they will go and make a show."

It's always special for him to glove up, whether it's in training or an exhibition.

"It's a feeling that just goes through your veins. It's a feeling that as soon as you put on those gloves, as soon as you lace them up and walk into the ring it's a feeling that overtakes your body and it's hard to give up," Barrera said.

"It's an adrenalin that you just don't get tired of and you just want more. So definitely just taking off those gloves is the hardest thing you have to do."