The problem with the Mascherano challenge is his studs were up, his leg was completely straight, AND he went over the ball. So in that sense it is a dangerous challenge as any significant contact to Ben Haim and you'd be looking at a potentially serious injury. In my opinion the red was right.
Arsenal not looking good here. Eduardo is just so short of pace and confidence its painful to watch. Song needs to keep things simple and stop looking to be the one firing balls up to the forwards.
As for Hughes getting pushed out of his job, I think it is disgraceful.