To me the most important thing was once it went to 2-1, despite possession, I can't really remember a proper chance they created. That's the sign of a very good team.
Overall echoing other posters game should have been over at HT.
I think the key difference on the 2nd half was that we were deliberately sitting a bit deeper and trying to string the counter attacks. The tactic was sound IMO, but first time in a whole the decision making and execution was off.
Execution bothers me less- we've got amazing players, sometimes passes just don't come off. But Silva KDB & Sane all made numerous incorrect decisions about where/when to pass as well as just misplacing the passes. I think tiredness was clearly a factor in this.