BJ Penn, the mixed martial artist otherwise known as “The Prodigy,” retired Sunday evening in Las Vegas after a TKO loss.

It’s a sad day for old-time fans like me — maybe, in a way a lot of MMA fans don’t understand.

So many have probably become fans quite recently, and really don’t understand the impact the pride of Hilo, Hawaii has had on the martial arts world. To be fair, recent bouts have not been kind to “The Prodigy,” who managed just one MMA win in the last four years.

They don’t get it. They don’t know that BJ was already a champion when he even came to the UFC.

It was fourteen years ago that a young and brash Baby Jay Penn entered into the Brazilian Jiu-Jitsu World Championships (the “Mundials”) to compete in the black belt division. He had only promoted to black belt a few weeks earlier, and in total had less than four years of Brazilian jiu-jitsu training.

At this time, coverage of jiu-jitsu tournaments was minimal to say the least. Martial arts magazines struggled to even spell “Mundials” correctly. If you wanted video? A friend of a friend at a BJJ academy may have a third-generation VHS tape from Brazilian TV coverage.

It would have been a huge accomplishment for Penn to travel to Rio and just be competitive.

But BJ Penn wasn’t just competitive. He won the tournament — the first American to win a Brazilian Jiu-Jitsu World Championship at the black belt level.

That was Penn. At his best, he seemed capable of the impossible.

PennStevensonHe continued doing just that in his MMA career. Jim Genia remembers the day Penn proved so much of the world wrong, jumping up a weight division to fight then-dominant UFC Welterweight Champion Matt Hughes. It was called a “suicide mission” by many, but Penn wasn’t just competitive with Hughes — he finished him in one round. Penn would later win the UFC Lightweight title, becoming one of only two fighters to win UFC gold in two divisions.

That was years ago, of course; Penn has endured a string of losses since then. Last year, I sadly described the mixed emotions I had about this latest comeback for MMA Frenzy.

Still, we kept wanting to believe he could make it happen one more time — but as we all know, it wasn’t to be. This last beating has sent Penn into retirement.

Some observers, even Daniel Cormier on commentary for Fox Sports, would remark that Penn didn’t show his best on Sunday. They say he had a bad game plan or struggled to make the featherweight limit, or something. They (okay, we) still want to believe. It reminds me of the talk after boxer Oscar De La Hoya’s disastrous last bout — which was in stark contrast to De La Hoya himself shaking Freddie Roach’s hand and saying, simply, “You were right. I just don’t have it anymore…”

Penn knows it. He would say after this last hurrah, “I shouldn’t have come back.” He’s right. It’s over, but what a career it’s been.

Now? BJ Penn can be a world champion dad, be a world champion husband, or maybe build a few champions at his academy. Maybe he can have a little fun and do a jiu-jitsu match — a “legends match” to bring a little glamor to a tournament. Whatever he wants.

BJ Penn was a champion who made you believe in the impossible. And, he still is.

It’s over for him as a MMA fighter, but no one in this game will ever forget what he accomplished.