But the most fearsome strike he's seen was one thrown by someone who sits outside the Octagon.
In a Q & A session for UFC Fight Club fans Friday afternoon at the Mandalay Bay Events Center, St-Pierre said he's never seen anything like UFC color commentator Joe Rogan's spinning back kick.
Speaking about time spent training at Eddie Bravo's gym, St-Pierre said "Joe Rogan was helping me out with the spinning back kick. Joe Rogan has the best spinning back kick I've ever seen in my life. It's incredible. If he was in a fight, if he hits anyone with the spinning back kick, I don't care who he is, he's going down. I don't care who it is, how big he is, it's amazing."
Mike Goldberg, the Q & A's MC, stepped in at that point and told people to check it out on Youtube, so we did, and it's pretty awesome. Don't believe us? Watch it yourself.
[ Video: Watch UFC 143 live on Yahoo! ]
Rogan's back kick was just one of many topics covered by St-Pierre -- who incidentally is now the second-longest reigning champion in UFC history, having surpassed Tito Ortiz's light heavyweight title reign -- in a half-hour question and answer session done in front of what seemed to be a majority of Canadian fans:
On his UFC Primetime comment that Nick Diaz is "fake crazy:" "What I believe is, he's a very smart guy. He knows what he's doing. He would not be able to do what he's done in his career if he wasn't smart. I do believe maybe he has some mental issues ... I do not believe he is a bad human being. Truth my eyes, because he has been very disrespectful to me and because maybe we'll fight, he's disrespectful, but to you guys, I'm sure if you saw him and asked him for an autograph he'd give it to you.
What if Carlos Condit beats Diaz on Saturday? "I wouldn't be surprised at all if Carlos Condit wins. I would not be surprised if Carlos spoils the whole thing. If he wins, you know, that means he's the best man, and I want to fight the best man. That means Nick Diaz would be out of a title shot and I want to go against the winner."
On whether Hughes should keep fighting: "Matt Hughes is an amazing fighter. It's just, at one point, I'm just concerned about his motivation, if he still has the fight. I'm concerned about Matt Hughes. Physically, Matt Hughes still has the skills, he can still kick ass. It's just up to him, does it still excite him, does he still have the motivation. I think he still can be one of the top guys."
And of course, there were the usual array of questions about fighting somewhere other then welterweight:
On the oft-discussed superfight with Anderson Silva: "It depends on the outcome on all the fights. Maybe if I beat the winner of Condit-Diaz, there will be another up-and-comer for me to fight, that everyone wants me to fight. Maybe Anderson won't be the champion anymore, maybe I won't be the champion. It depends on the outcome."
From a clearly inebriated fan who asked him if he'd fight at 205: "I do training with bigger guys, but a fight is different than training. If I would go [straight to 205 from 170], it would be the stupidest thing I've ever done. It's like you're asking me who would win in a fight between Spiderman and Batman."
On going down to 155: "If I go down to 155, Frankie Edgar will kick my butt."
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