There's a lot more wrong in his game then a couple of poor crosses and a few failed dribbles.
It's not like he was lacking in confidence against Burnley at home, or Liverpool away, either. And even then, it was quite obvious what he is and isn't good at. He's a player that relies on dribbling, more than passing and moving. Unless we're set up to counter, our attack favors short, intricate passing in wide areas, so as things stand, he just doesn't suit the requirements for that particular role. Which is the most reasonable cause for his down turn in confidence.
He's not getting the very basics right, and that's usually down to a lack of competence than a lack of confidence. I brought up Walcott and Ramsey because they were in the same boat. Players with standout attributes, which when the circumstances afforded, shone through. But other times had huge holes in their game (one thing that always pissed me off about Ramsey was how the most basic short passes were always bobbling and never quite to the man). And the thing they all have in common? All three got into football late.