The Gunners, who were leading the league before the weekend's matches, crashed spectacularly at Anfield just as they did when losing 6-3 at Manchester City in December.
After that disappointment, the north Londoners went on a run of eight wins and two draws in 10 matches and defender Mertesacker wants something similar to reoccur.
"We feel very bad, disappointed with our performance right from the start. To be honest, it is one of the worst setbacks of this season," Mertesacker told Arsenal Player.
"It was just not good enough to compete at that level.
"We have the opportunity to respond quickly on Wednesday and we have to remind ourselves what we have done from Manchester City until now.
"That is at stake, and to show that responsibility for ourselves and for the pride of our club."
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