I went back to watch the incident with Watkins again - because it was soon after Cavani goal sometimes it's easy to miss the details. At no point is it obvious that he was going to control it, he does not even attempt to control it because he sees Deano's long leg is there already. During the fall he positions his body as best as he can to get contact with Deano but doesn't get it because he was too far to begin with. Goes through with his swan dive anyway, stays down and cheekily looks back at the ref as if asking for a penalty. To his credit he does not simulate injury - he at least has common sense enough to not writhe around in fictional pain and that's all I can say.
I say on principal it's warranted. A tad bit harsh because it was a second yellow but I would also accept it if it was one of ours getting that second yellow. And I would certainly not be a twat about it like Dean Smith was.