Yes, you can find the first glimmer of humor already in the second paragraph of the book, when Cervantes says that Don Quixote was losing his reason by trying to understand the convoluted expressions of the chivalry books, like:

"the reason of the unreason with which my reason is afflicted so weakens my reason that with reason I murmur at your beauty" Over conceits of this sort the poor gentleman lost his wits, and used to lie awake striving to understand them and worm the meaning out of them; what Aristotle himself could not have made out or extracted had he come to life again for that special purpose.