I thought he was superb. Don't mind his reactions either. He plays with a lot of passion, so the emotions are bound to come out. Not to mention that he should have got both the corner and the throw-in. It's easier learning to control emotions than to add hunger and commitment to your game, mind.
Let's hope he keeps this up. If he keeps impressing, I'm sure he will find a Premiership side to go on loan next season. Then he can really force himself into Wenger's plans.
I love that he's tenacious, agile, pretty quick, has good stamina and doesn't shy away from physical battle. With the inevitable physical development he will go through in the next few years, I can see him turning into just the type of midfielder I like best.