Probably no more than he did for the first one. He is a "learn by doing" person. He likely knows what opportunities he missed.
-- not taking the debates seriously is hurting him. --
He takes them seriously. He is not working like the typical politician. he knows the debates aren't determinative, and at this point he is quite the risk taker. The next debate is a town hall. He does exceptionally well in face-to-face with "constituents," especially in that he does not pander, yet still shows empathy.
-- I'm truly baffled H. Clinton can have as much support as she does. --
The world is a strange place. I believe she has support, and lots of it. But I still feel that Trump has a substantial advantage in this race. I'm not worried, FWIW.
As someone pointed out here ILLary has all the support of the addicts. They don’t want their source to dry up with closed borders. I know that to be true for two people I know personally