The North London club are set to take on fellow London outfit Brentford at the weekend.
As he prepares to go head to head against Thomas Frank, Postecoglou praised the Danish manager’s work.
He stated: “A great challenge. Thomas has turned them into a really difficult and challenging team for everyone in the league.
“I saw them last week against City, I thought they played really well, took the game to City. It’s always a challenge, but that’s the Premier League. I don’t think there’s any games you go into thinking they’re going to be any easier than any others.
“We’ll have to be ready for Brentford tomorrow, but we are at home and we’ve just got to make sure we continue with our strong performances in the league but turn those performances into results.”