His transfer generated a massive media frenzy, that built up over several seasons on top of that. That's a lot of pressure on a young player. Hard to compare that to say the transfer of Fernandes, or even Ronaldo's transfer that just happened over night. (Not that Ronaldo would ever let that kind of pressure get to him).
I think you also have to take into account that it's the first time in a very long time in front thousands of fans so that all contributes to him probably being nervous. Naturally he isn't going to be the first player his team mates seek out yet, so when he does get the ball he probably overthinks. That'll settle with time