Spurs' all-time record goalscorer Kane joined Bayern Munich just 24 hours before Tottenham got their season underway on Sunday.

Scoring was not the problem for the visitors in Postecoglou's first competitive match in charge as defenders Cristian Romero and Emerson Royal struck early and late in the first half.

But in between times, Tottenham's defensive frailties were exposed as Brentford equalised through Bryan Mbeumo's penalty and then went in front thanks to Yoane Wissa's deflected effort.

"It is either an impediment to you or an opportunity," said Postecoglou of Kane's exit.

"Harry Kane was massive figure for this club for a long time and will continue to be whether he is in the building or not.

"We wanted to go out and give our supporters some hope and belief in the team. I thought they did that today."

Postecoglou took the decision to remove Romero shortly after he had opened the scoring on 11 minutes due to suspected concussion despite protests from the Argentine centre-back.

The Australian coach said he had no regrets over that decision, but criticised the fact it did not count as a concussion substitute due to the wrong form being given to the fourth official.

Premier League sides are allowed two extra substitutions, on top of their allocated five, to replace players suspected of suffering concussion.

"Their (medical team's) information was that he wasn't that steady and with his head after scoring, I'm not taking any risks in that scenario in this day and age and what we know of head injuries," added Postecoglou.

"The last person you want to be directed by is the player himself. He has no idea. The disappointing thing is that apparently we filled out the wrong form for a concussion sub.

"That is madness in this day and age. It is pretty clear why we took the guy off. It is black and white for us, we're not going to take any risks with our people when we know what the repercussions are."