The Yorkshireman stepped off the bench to rescue a point for City with a stunning free-kick, but the late drama could not mask an average performance overall.
City now trail Chelsea by seven points and are without a win in five games in all competitions.
Milner said: “It’s not good enough. I think coming off the back of a good performance last week against a top team and coming here we knew we’d be up against a spirited side who were desperate for the points and we’ve slipped up again at home.
“You can look at a few things but over the 90 minutes I don’t think we troubled them as much as we should have done. For whatever reason we’ve struggled at home this year and dropped far too many points.
“It’s a flip from last year when our away form was poor. This year it’s the other way around so it’s disappointing but we need to regroup and come back and try and put a run of results together.”
When asked how costly the dropped points could be Milner added: “Very. Success in recent seasons has been based on solid home form, last year, I think we drew one game at home, so that shows that we have to make the difference away from home now and can’t really afford too many more slip ups if any.
“I’m sure Chelsea will have a big lead now but it’s down to us to concentrate on our game and see how many points we can get.”
