The team suffered defeats in the Champions League, Premier League and FA Cup in quick succession in recent weeks.
But they bounced back to defeat Bournemouth in the league and now have some momentum to go into their second leg round of 16 tie with Atletico Madrid.
Milner admits they can suffer drops in performance, but admires how they always fight back.
He told the club website: "It's always going to happen. No team goes through a season without having a couple of performances which aren't at the level.
"It happens, it's a long season and you see how many games we've played, and any sport you play it's impossible to be at your highest level all year, year in and year out.
"You try your best and it just doesn't happen, and that's when you need to find a way to win. We've done that but we need to get back to the level that we know we can perform at.
"But the boys are working hard, you can see that it's not through a lack of effort and the two finishes today were clinical from the lads up front.
"We could have closed it out as well but they had chances as well, so there's plenty to look at on what we can improve on."