It was a red, but I hate these kinds of reds where basically both players go for the ball and one of them reaches it a tenth of a second faster and the other pretty much can't avoid fouling him. Then it's a matter of utter spatial randomness and a few centimeters to determine whether it's a yellow that has no real bearing on the match, or a red that completely changes the result. You're going for the ball and suddenly there's a foot right where you're about to place yours in the next instant. Unavoidable, unintentional, but the rules are the rules and the red is correct.
Minutes later there's an essentially identical challenge in the other end of the pitch, but because one player steps on a different and less painful part of the other's foot, it's not a red. It's pretty much a roll of the dice. So fecking unlucky, and now it might make an otherwise comfortable CL group much more troublesome. It's not as if AWB shouldn't have gone for the ball, just rotten luck.