Well, the red card (against an already very weakened team) pretty much guaranteed the hosts going through. Job done.I think it's a red, it was a pretty poor tackle. I think the telling thing was just how far away he was from the ball. With that tackle, he knew he was fouling the man, with no possibility of taking the ball, so it's a yellow.
But then, the question becomes was it dangerous or reckless, likely to cause injury - in my opinion it was, studs down on the ankle.