Don Frye
He is an ex-pro boxer with beat he crap out of Amaury Bitetti, a BJJ champ at the time, in UFC 9. But, mind you, he had collegiate wrestling, Judo, and Greco-Roman in his skillset. He came in claiming boxing though as his style and beat Bitetti without ever going to a 'ground fight'. Every time this guy went for the shoot he caught a knee in the face. When he was forced down from the sprawl, Frye dropped elbows down on him. It did end with a ground and pound I believe.
Anyway, a great example of a pro boxer beating a renowned BJJ/MT guy. I think Bitetti was training with Ruas at the time.
But as the general argument goes, this was an exception to the rule. Usually, the boxer becomes the fish out of water as soon as he's grabbed. Frye has/had significant grappling knowledge to help him out there.
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There are no PERFECT techniques, only perfect execution for the situation at hand.
~Corwin