Jurgen Klopp's side swept the 'Gunners' aside that day thanks to goals from Roberto Firmino, Sadio Mane, Mohmed Salah and Daniel Sturridge and Wenger admits that the result still hurts him ahead of Friday's rematch.
"When you have such a long career as I have, you have some defeats unfortunately that hurt you for the rest of your life," he explained ahead of the game.
"I believe what is interesting in football is you always have a time to make up for it. When you can put things right, do it.
"So let's focus on what is in front of us and turn up on Friday night with a completely different performance.
"The motivation is there. This squad has a good mentality and it is about us, to make sure we are on top of our game. We must play with pace and a determined attitude."
Alex Oxlade-Chamberlain took much of the stick on that day in August, putting in an insipid performance before heading to Anfield on deadline day, but Wenger refused to blame the winger for Arsenal's defeat.
"It would be not fair to put the defeat at Liverpool, where the whole team had a bad performance, on one player," he said.
"After that, on the other side, you analyse 'did you make mistakes or not?' You cannot go home and say everything was perfect when you lose like we did.
"I rate Alex highly and he knows that. After that, you want all the players to be respected who have played for us."