In a post-match interview with Sky Sports, Postecoglou said: "It wasn't good enough and I have to take responsibility for that, it is on me. I am the manager and I am the one putting them out there and it was not good enough. When we put in a performance like we did in the first half it meant my message wasn't getting through."
However, the Aussie lost his cool when further pressed about what message he particularly tried to get across to his players.
"Come on mate, we didn't play well, do you want me to write you a dossier of where it went wrong?" he asked.
"I feel like we've lost a bit of belief and conviction in our football and that is on me to change that. It wasn't about conceding the [first] goal, it was our approach to playing football and we were nowhere near good enough. That is on me.
"We've been in a bit of a grind for a while now, that is part of our challenge and part of our growth. We have to go out there and perform and sometimes you have to grind out. We were poor today."