By the new, absolutely moronic standards, that is a penalty and it should be a red card. No different to David Luiz being sent off because the guy kicked him in the knee on his backswing, apparently it now doesn't matter if you don't even attempt to make a challenge, if you impede a striker then it's a penalty and if it's an accident it means it wasn't an attempt at the ball, so it's a red.
It's stupid as fuck, but it is the rules at the moment. (expect them to be changed in the wake of this game though as the media will all of a sudden realise it's shite)