I think the problem is that him and the players around him aren't quite on the same wavelength yet. Last night he clearly wanted the ball in behind to run onto and the one time he got a really good pass to set him away it led to Sancho hitting the post.
Most of the time he was getting the ball into feet to either play a pass back or turn and run and he struggled with the latter a little because he wanted more time than he was getting. The premier league is, by a fair distance, the strongest league in the world and one thing defenders have to learn to survive is to not let attackers get turned without a challenge. This means forwards and wingers coming in then have to learn how to ride that early challenge. He's big enough and strong enough to get there, he just needs to work on it. A run of games will help him so I hope he gets given that chance before we dump him as not good enough.
Aside from that I thought Henry played excellently and was their best player by a long way, which made it tougher for Guessand to get into the game as well, and with them playing a back 5 there was less space to begin with.