Arsenal were without England international Declan Rice who was ruled out through injury while Jurrien Timber, although named on the bench, was not fit enough to feature.
"We missed half of the team again and you can still [come back] from 2-0 at Anfield," Arteta said.
"We played the way we played, came back and maybe should have won it, and at the end maybe lost it with something that was in our hands.
"If we want to really win it, the consistency level [has to be there] for 95 minutes.
I am disappointed."
Arsenal have now won just one of their last six Premier League matches and need to pick up points across their final two fixtures to secure second place.
It is a big opportunity.
"If you cannot be the best, then you have to be the best of the rest.
"That is very important.
"That is what we have to demand from ourselves."
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