Lesnar did not get lucky. He outsmarted the engineer. He let Carwin punch himself out and then used an arm triangle that he had been rehearsing for weeks.
One thing for sure though he doesn't really take a punch well no matter what people say about the last fight. He crumbled and backed off very much like Bob Sapp does. He's not used to getting cracked. I pick Cain to hurt him and make him cry.