That was like an FA Cup game when you get a second division team vs a EPL heavyweight, snatch a goal and defend all game. Its a bullshit tactic. PSG don't defend that well so that should be your focus, and trying to get corners because it's your best tactic. It was a wasted opportunity for Arsenal, PSG were poor.
Also, our loss to Barcelona was because of some key moments, we played a good game and kept up against one of the greatest teams ever. Cardiff was a scared performance, we we no threat.
Last point, the UCL has been won by ultra rich teams. Only Dortmund have threatened and it's because they will always play their attacking brand of football and trust youngsters.