Former welterweight champion Matt Serra spoke with MMAJunkie Radio about BJ Penn’s retirement and how he understands why the Octagon drew Penn back in for one more fight.

“I know why it’s hard to walk away from the game,” Serra told MMAjunkie Radio a few days after cornering UFC middleweight champion Chris Weidman in his UFC 175 victory over Lyoto Machida. “Trust me, I know.

” … That feeling – to know you’re never going to have that feeling again? Listen, man, when you have a good night, get a knockout, finish somebody – oh my God, it doesn’t matter anything that happens after that. That single moment, nothing can be wrong in the world. That’s where your head’s at. Cloud nine is an understatement.”