He was disappointed with Spurs' passive approach, noting they failed to play to their identity.
Despite the setback, Postecoglou remains focused on upcoming competitions, emphasizing the need for his team to stick to their style.
He told ITV: "Tough night. Credit to Liverpool they were way too good for us tonight. We never really got to grips with the game with or without the ball. We just allowed them to get control pretty early and it made it difficult for us to get in the game.
"Both of the first two goals we could have done better but ultimately what was really important was that we never played to our identity and strengths and shied away from the challenge a little bit.
"Overall we didn't start well and were way too passive and let Liverpool get in a rhythm. We still have competitions to play for starting on Sunday. With the opportunities we do have still, we have to tackle them in our way rather than finding different ways to win games."