I'll give you Sagna should have seen a yellow if Richardson did but that doesn't make a bad game
As an Arsenal fan who watches Mertersacker week in week out I can tell you he's often clumsly falls over as happened when he came off so I'm confident it wasn't intentionally. He wasn't even looking at the ball when it his arm.
You can go through the back of someone with your shoulder, the point was he went for the man not the ball and it was more that a simple shoulder to shoulder. A previous comment tried to indicate that RVP just lost out to him and I countered that by questioning how RVP could do that if he couldn't see him
Your best player appears to be Sessegnon who you're incredibly lucky didn't get a red card at the end and have to serve a 3 match ban so i wouldn't be too mad with the ref
Both teams played ok not great, you tired towards the end and we capitalized...simple as...ref didn't lose you the game