Unai Emery admitted Arsenal have "a lot of work to do" after they were thrashed 5-1 by Liverpool.
The Gunners took the lead in the 11th minute through Ainsley Maitland-Niles, only to concede four times before half-time.
Roberto Firmino added a fifth in the second half as the Gunners slumped to a heavy defeat.
Emery said afterwards: "I think we started well, but after our goal, they pushed, and when they push here, they play with great determination and with players who can make a difference all over the pitch.
"They scored three quick goals and it was a difficult moment for us. We spoke in the dressing room - it's another experience for us. A bad experience but an experience to learn from.
"In the second half we needed to stand up, to keep our position individually and collectively on the game. The two last goals, two penalties, I think it's a lot for us.
"I think VAR is important - it's coming next year, because I think it's going to help the referees to take better decisions. We only can think now of the match on Tuesday [against Fulham] and know the difference between Liverpool and us was not like today's result.
"Maybe we can do one balance, one mix between our draw and this result today. We have a lot of work to do, defensively also, we know we need to get better."
Emery highlighted Maitland-Niles and Alex Iwobi for their positive displays, but said Arsenal lacked balance.
He said: "Ainsley played as right winger and scored, working well. Also Iwobi, after some matches not playing very well, today he played 90 minutes with a good performance.
"But defensively we need to be stronger, to work. Our defensive moments in our box, it's my responsibility and then we need the balance. We need to keep the balance in the middle.
"We lost today 5-1, we need to keep the balance in the middle, be serious and continue on Tuesday with a big match at the Emirates. We need to show our supporters there we are standing up after the result."