The Bees - seen by plenty as the close season title-favourites heading - came unstuck in west Yorkshire on opening day.
A year ago, the Shaymen defeated Bromley who of course went on to secure an EFL place for the first time in the club’s history.
Goals from Jamie Cooke and Adam Alimi-Adetoro meant Halifax made it hell for another fancied side but manager Millington knows Dean Brennan’s team will come good.
But he warned the rest that his team will only get stronger as well.
Asked by the Halifax Courier if he had seen the result coming, Millington said: "Always, I always expect us to win. In my time here, we've never played a team where I've not believed we've had enough to win.
"Barnet will get better and so will we. By the time we play them again it'll be a very different situation and I expect both teams to be paying with more quality by then.
“We're a young group, but what they are is a group of good learners.”
Next up the the Shaymen is another home game, this time with Aldershot.