Spurs won 3-0, despite losing Radu Dragusin to a seventh minute red card.
Brennan Johnson, Pape Sarr and Dominic Solanke scored the goals for Spurs.
Postecoglou later said: "Yeah, I thought again Brennan was really important for us, particularly today going down to 10 men pretty early, we're going to need some attacking outlet and I thought he, Dom and Sonny provided that and obviously we needed a goal.
"I thought it was a good first goal for us because we were with only 10 men, but we still pressed and forced a mistake and Brennan's been good at taking up those positions and him and Dom have a good little sort of relationship there in terms of working off each other and he took his goal well. As you said, that's three in three games for him, and long may it continue."
Lucas Bergvall was substituted on 12 minutes for Destiny Udogie to adjust to Dragusin's dismissal.
Postecoglou explained: "Nothing specifically to them. I mean, it was just a consequence of us starting the game really slowly. It was just not a great start for us. We were really passive with our passing. Whether it was the delay to the game or whatever, but it's no excuse.
"We kind of shot ourselves in the foot and unfortunately Radu and Lucas paid the ultimate price for it. But as a team, we just didn't start the game in the way we wanted to and the way we needed to and made the game challenging for us. The response was great, absolutely, but disappointed we had to be in that position."