Prior to the fight I thought "what a clown, Klitschko will take him apart in the ring".
That seems to be what Klitschko thought as well.
What happened in the ring is that Klitschko was confronted with an immensely clever boxer who could switch hands, box clever, fast and heavy, hit clean and hit dirty. Klitschko was outsmarted, outclassed and (despite looking much fitter) confronted with someone who didn't let up, didn't tire out.