Just on the sending off; van Persie seen the linesmans flag, he was looking straight at him. So regardless of the whistle being heard (which I don't believe for a second after it didn't happen the rest of the game with any other player) he knew he was offside. And given that, he's an absolute plum for giving the ref the opportunity to enforce the rules he's supposed to be enforcing and getting marked on by the UEFA supervisor. He'd seen Sagna (?) getting booked earlier for throwing the ball away, and Arsenal had been timewasting a bit as well. That's beyond idiocy, and the fact that it's all that will be mentioned by Wenger is a shame.
The reason that's a shame is because he won't be asked about parking the bus which is what he did. No shame in that against Barcelona imo, but don't come out and talk about how your side is the virtuous one when you do that. For a side at this level to have no shots at goal is simply pathetic. And it was nearing an hour into the game when van Persie was sent off, not 10 minutes in, so they'd already went two thirds of the game without having a shot.
The worst decision the ref made was the non awarding of the penalty for the foul on Messi by Koscielny. Koscielny who could well have been sent off for some other fouls after his booking btw. And I'd also add that on at least one occasion after that penalty shout Pedro (I think) stayed on his feet when he got clipped in the box. I dare say there will be the usual "Platini hates English clubs and gets the refs sent out to nobble them" shite, but have a think about it ffs.