Definite foul for me, Stones misreading the ball is irrelevant, he was in front of Firminos path to the ball at every stage, therefore it wasn't a coming together. It also wasn't shoulder to shoulder it was an out stretched arm that caused Stones to stumble and gave him a clear run at the ball he would otherwise not have gotten, thus an unfair advantage. Can't see how anyone can begin to claim otherwise, would have been a penalty if a player gets that from a defender through on goal, should be the same for a defender no matter how strong we expect them to be.
What gets me is the cheeky dippers who all reckoned it wasn't tried to say Raheem fouled VVD for our opener in the CL home leg, which was an unavoidable coming together caused by VVD trying to keep a ball he'd overrun in play... you couldn't make it up.