He wasn't really in good shape earlier in the season, in fact I'd say he's still not near his best level. Wouldn't even surprise me to hear some months down the line that he has been playing with a small injury, just like Mandzukic last year with those months below par.
Seen enough of him last year when he finished several chances in a striker's fashion. He averages about 1 shot per game so I don't know how he manages to miss lots of chances.