The Premier League side were beaten 1-0 by Nottingham Forest away from home to compound their woes.
A sole Anthony Elanga goal was enough to settle the game, with Postecoglou’s side unable to score goals.
Post-game, he said: “It's obviously disappointing the defeat, tight game, it was never going to be the kind of game where there would be too many chances. I still thought we had a fair chunk of it where we could have got something out of the game, but it was always going to be a tight game here.
“It was a disappointing goal we conceded, but aside from that the boys worked hard and we tried to generate as many opportunities as we could considering the context of the game and how Forest play, but we just couldn't get over the top of them.”
Adding on the lack of goals, he said: “It’s a bit of, like I said, game state. I kind of knew that if they can get a goal up, it was going to get even tighter for us to find space behind them. It was never going to be a game with a lot of opportunities.
“Having said that, I still thought we created some good ones and we just weren’t able to capitalise on them. The keeper has pulled off a couple of good saves to keep them in the game.”