Via Cagewriter:

The times we were on our feet, I was more successful, but the bad news was that we were only on our feet for about 15 seconds in the round and a half that we fought. I got pretty much owned on the ground. I need to work more wrestling, and I also need to put on a little bit more size. I think 245 was a good weight as far as maybe everybody else in the heavyweight division, but fighting Brock, there was too much of a size difference, due to the fact that he had great technique also."

"It wasn't just because of his size that he was able to nullify my technique, but he used his size. He knew how to position his hips, and block my hips, and hold my arm. He did things that I didn't really expect because of his reach. I think I went in with too much of a gameplan, and I wanted it to go one way, and I tried to force it that way.

It took a while, but at least he didn't attribute ALL of Lesnar's success to just sheer size.  Well done Frank, you finally exhibited some humility.