Arsenal boss Mikel Arteta wants his side to return to the standards he has set for them as they face a London derby at West Ham.
The Gunners underperformed in a 1-0 Europa League defeat to Olympiacos on Thursday night but advanced into the quarter-finals with a 3-2 aggregate win.
Arteta said after the game that his side would need to improve if they are to progress further in the competition, having been drawn against Slavia Prague in the last eight.
He knows the quality of the performance will also have to be higher to get a result at the London Stadium on Sunday.
Asked what lessons he could take from the loss to the Greek champions, Arteta said: "Basically that we have to maintain the standards that we set.
"Particularly when we are in possession of the ball – we had too many situations where we didn't discriminate or make the right decision and then execution-wise we weren't at our best.
"We know we will have a really tough game, they've been in great form, they've been really consistent, they know really well what to do and how to hurt opponents.
"I know David (Moyes) really well and I am sure he will prepare the match so it is a really difficult game for us."
Arteta revealed on Friday that Moyes had a big influence on his managerial career, having played for the West Ham boss when he was in charge of Everton.
Because of their shared experiences, Arteta insists he is not surprised Moyes has turned the Hammers from a side fighting against relegation to one challenging for a place in Europe.
"I think they have a really strong squad and they have a great manager and coaching staff," he added.
"They started the season with some doubts but I know what David is capable of doing.
"Obviously they have a little bit more time during the week to prepare football matches and training, and I think they've been in great form and they're a really dangerous team."
