The team lost 3-2, with Swansea scoring twice in injury time to secure a second defeat in Postecoglou's first two games in charge.
According to reports, Postecoglou was overheard speaking to his players in the dressing room immediately after the final whistle, expressing his disappointment with their performance.
When speaking with the media, Postecoglou said that the team should have been more prepared for the game and handled it better.
He emphasized that the focus should be on the team's progress and creating an environment for success, rather than individual performances.
