Arsenal goalkeeper Petr Cech says Philippe Coutinho's impressive free-kick shifted the momentum of the game towards Liverpool.
The Reds took all three points from the Emirates after coming from behind.
They took full advantage of Arsenal's problems in the defensive department as the Gunners were without Per Mertesacker, Gabriel Paulista and Laurent Koscielny at the back.
Arsenal are away at champions Leicester City next week with Liverpool away at Burnley.
"We had a great start to the game," Cech told Sky Sports.
"We were organised and controlled the game. It was disappointing to miss the penalty but the reaction of the team was great because we broke through.
"In the second half, the momentum changed because of the free-kick.
"Liverpool came out with more ambition and were very aggressive. We were punished by the Lallana goal and once we fell behind we opened the game too quickly and allowed them three, four, five counter-attacks."