That PSG goal right at the start changed everything I think and you could tell that Arsenal had to work harder than they had planned which left them very exposed, Donnarumma was everywhere making those saves and you could tell that PSG weren't playing defensively they stayed focused the whole time even when Arsenal started to throw themselves into attack in the second half, the way the game unfolded after that first goal made Arsenal look a bit desperate and gave PSG some good chances to break the deadlock, I think if PSG keep playing like this and maybe try to score another early goal they could knock Arsenal out.