For some odd reason, I've been surrounding myself with a lot of jiu-jitsu guys for the past two months and every single one agrees that Roger Gracie is the greatest jiu-jitsu practitioner in MMA. A few even claim that Roger Gracie is the most skilled Gracie in the entire family. The accolades, however, did not serve as a forcefield to protect Roger Gracie's chin last weekend at the Strikeforce Heavyweight Grand-Prix. It took just one clean straight for King Mo to capitalize on a first round victory in his first fight since Strikeforce Houston in 2010. At least that's what most people thought. In an interview with TATAME, Roger Gracie says that at some point, King Mo accidentally headbutted him which was the cause of the knockout.
“I couldn’t do what I have trained to do back then. I believed in my jab and he (King Mo) wasn’t bringing much danger,” he said. “When I heard Renzo (Gracie) saying there was a minute and a half left for the end of the first round, I relaxed. I didn’t have enough time to submit him nor take him down, he wasn’t punching me, so I thought I would keep it that way until the second round. That was the first mistake. The second was that he accidentally hit his head against mine, and I got dizzy. I moved backwards, he punched me and I felt. That head was practically an accidental knockout. When I tried to grab him, clinch, his head hit my face and I backed of”.
“I was supposed to work on the clinch, because I wouldn’t risk trying to grab his legs and take him down because it wasn’t the beginning of the fight, so I wasn’t using much energy with no purpose. I was supposed to work on the clinch and take him down. And during the first round I didn’t try to do that, and suddenly I realized the danger he was putting me in. Losing is terrible. Nobody likes losing, especially being knocked out. But what can I do? I’ll train so it won’t happen again”.
Interesting that engaging in the clinch was the perceived method of victor for Roger. Granted, it's tough envisioning Roger taking down King Mo, but closing the distance just opens one's chin to Mo's Cuban-style boxing -- essentially lowering one's hands to bait an opponent in and using speed (and overhand rights) to damage your opponent. [Source]