I understand now this is definitely not a combat situation Brennus is comfortable with. My mistake. I took too many liberties in the opening post. 

Brennus would destroy Florian in a contest of strength, absolutely no questions. That move specifically doesn't require strength though, as Vordak said, which is why Florian was confident in using it. He stops Brennus' blade with the strong part of his own, and then grabs his wrist, preventing him from making any serious attacks, and then striking for the kill. Very quick and painless. That's how it would happen in the totally hypothetical scenario that is not the one described in this fight -- if you were to continue the example I offered, I mean.