Matt Serra chuckles. He's been asked to talk about this so often, over the years.

I don't care. I want to hear about it from him, myself. So, he kindly readies to do it again - reminisce on his world title win over Georges St-Pierre back in 2007.

The retired former champion is now in his 40s and hasn't sparred in years. These days he's busy raising kids with his wife.

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In fact, he's busy doing that during this very conversation at his home as he takes care of one of his daughters, trying to keep her out of the everyday perilous situations that little kids find themselves in every day.

"No, no no, don't do that," he says, at one point. "Come here, get away from that," he has to instruct at another.

Of course, Serra also has his hands full coaching top fighters like Chris Weidman and Aljamain Sterling, as well as other students at his three Brazilian jiu-jitsu academies. That's to say nothing of his new reality travel/food show with UFC president Dana White, "...Lookin' for a fight."

Matt Serra is busy with so much lately, but on this particular day, April 7, we can't help but ask him about that night in Houston when he shocked the world and ensured his own place in history.

Serra won season four of "The Ultimate Fighter" to earn a title shot. Most observers in the fight world thought the prize of getting to fight St-Pierre a particularly cruel one.

The young champion was still early in his reign but looked so dominant getting there that it was assumed that he'd go on to have a long and peerless career on top.

He would. But first, Serra knocked him off the mountaintop for a bit.

St-Pierre couldn't become who he became without having to fight through and past the beating "The Terror" put on him that spring night in 2007. Serra didn't just survive or eek out a win over St-Pierre, he knocked him out.

It immediately became the biggest MMA title upset in history.

The day we visited Serra was the nine-year anniversary of that fight, which probably still is the biggest upset the sport has yet to see.

"I knew what I was going into," he begins, talking about his challenge of the greatest welterweight - perhaps the greatest fighter at any weight - of all time.

"I've said it before -I really just felt like I was in a movie the whole time. The pressers, everything I was saying, the week of the fight, the night itself. I just couldn't have worked it out more perfectly."

As surreal as the fight's ending - Serra mounted on St-Pierre, battering him with heavy punches as the champion flailed - seemed to fans around the world, it may have been more so for the Long Islander himself. Serra always believed he could beat St-Pierre, but that still didn't prepare him for the moment after he'd actually done it.

"What happens in a fight is that, when you're in the thick of it, you're just zoned-in to the fight," he explains.

"The second [referee] 'Big' John [McCarthy] jumped in, it felt like I had been pounding on him for an eternity (laughs). Then, I was like, 'that's it?'

"It was a surreal moment. When you watch the fight you see me and it looks like I lost my mind. Like I was about to start flipping out. Then, I did my little one-handed cartwheel, looked up and just kinda soaked it all up. If there's a movie of my life, that's where it ends. Sure you could show me ending [Frank] Trigg's career, and punching [Matt] Hughes in the face, but that's the big moment. In the ending credits they say how I lost to GSP in the rematch, but that's not an important part (laughs)! At least not to me!"

All of 2007 was a bit of a heady time for Serra. He won TUF, beat GSP, became champion, got married, shot another season of TUF and finally became a household name among MMA fans.

Though he isn't an active fighter anymore and nothing could be as hectic and fast-paced as that year, Serra enjoys where his life has ended up.

"2007 was an amazing, whirlwind of a year. The press that followed the title win, I got married a month and a half after winning the belt. It definitely made the wedding that much better. We had 300 people. It was a Godfather-type wedding," he chuckles.

"Everything was perfect. After the wedding we went to Aruba for our honeymoon. Then, two days later, I went to shoot TUF 6. It was busy, busy. At some point around then we started doing video blogs which led to good things. We switched gears. And now, somehow, nine years later, who knows why, I'm still relevant."

Humble as he is, Serra is far more than relevant. Along with his coach and friend Ray Longo, he's become one of the best coaches on the planet, producing champions and contenders, and his charisma and good humor make him one of the most in-demand interview subjects in MMA.

Though he undoubtedly would have liked to have been able to beat St-Pierre in their rematch and stay champion longer, Serra insists that he's not that guy. He's the neighborhood guy who made good.

"I'm not the guy to be made champ and hold onto it for a long time," he admits.

"I'm a 'tweener. I wasn't huge for 170 but I was a little too big for 155 for whatever reason, because I'm so wide (laughs).

"My role is the underdog guy, and I'm happy to be that. Nine years later, I'm at Penn Station this morning going to see a friend of mine in the city, and I'm still getting stopped by fans. I didn't expect that. Back in 2001, I'd go get a fight here and there. I'd come back to New York after a fight in Vegas and tell my buddies that people were asking me for autographs at the hotel and they wouldn't believe me. Back in the day, I wasn't doing it for the money, because there was no money in it.

"I was doing it for the life experience. I never wanted to have any regrets. So, whenever a shot was presented, I took it, and it led to good things. It has been a roller coaster. TUF was an amazing opportunity and I seized it. Out of that, I got another amazing opportunity and I seized the hell out of it. It is the gift that keeps on giving."

Serra has too much perspective to get caught up in the trappings of celebrity, it would seem. Of course, the gregarious guy enjoys fan attention, but his self-worth isn't built on adulation.

He knows who he is because he took his shots and saw what he was made of. He fell in love with Brazilian jiu-jitsu, so he devoted his life to it.

He wanted to test his jiu-jitsu, so he fought, and fought whoever they put in front of him. It all happened to end up affording him a living, and he's grateful.

But he's grateful simply because it means he gets to continue training and teaching, and because all that lets him support the family he loves.

"I'm always going to be the guy that's very fortunate. I'm doing what I love and, really, I've been doing what I love ever since high school, because I've been training," he reasons.

"I was doing what I loved and was lucky back when I was making ends meet by teaching private lessons, and by grabbing a fight or a grappling match when I could to make extra cash. I tell guys that, while you don't want to rest on your laurels and you have to keep your eyes on your goal, you should appreciate and enjoy the journey.

"There are times where I look back, now, and I am extremely happy. Back then, you felt like it was going to be over at any moment. When I was living with my roommate Rodrigo Gracie, I remember thinking I just hope this doesn't end. In a way, it really didn't. I remember sitting on the apron of the ring at Ray Longo's gym as a 20-something year-old kid, and Long was probably the age I am, now. I told him, 'Dude, wouldn't it be great if we were doing this forever?'"