Edit: To Judoka.
So, you don't think he can win the fight in the clinch with his dirty boxing?
I think it is wise for him not to go into the clinch if there is something else he can do. Stay away from Lesnar's strengths and exploit his weaknesses. Randy has very technical stand up and as Sylvia found out, hard to hit. Lesnar although we have seen very little seems to hit extremely hard to hasn't got technical striking like Sylvia does so Randy shouldn't have a massive problem with that unless a big shot lands but if that happens most of the time you are in trouble, not mattering which fighters are in the ring.
Randy could go a bit into the clinch and dirty box, he is good at it. I am not a wrestler(Hardly any in Australia) so I am not exactly an expert on it so I can't call on all the strengths Lesnar is bound to have. Randy is a much better tactician then me so he may do other things and they may work, he is a very smart fighter.