Tottenham and Manchester United face off in one of two Saturday evening games.
The match is a huge one for both sides but is especially important to Tottenham.
They missed out on European football last season and have now lost Harry Kane.
As a result, picking up a win over a European rival would no doubt boost confidence.
But Postecoglou is more focused on picking up a convincing win over the Red Devils.
Asked how important it would be to beat United, he said: “Getting just a win, I don’t know if that does anything.
“If we go out there and win 1-0, but we’re not convincing in our performance, we’ll feel good for a couple of days but it will not give me any real solace that we’re heading in the right direction. A strong performance is what we’re after.
“Obviously we want to win, that goes without saying but you want to win off the back of playing our football, showing signs of progression from last week, trying to impose our game against a really good opponent and win that way and that is how you accelerate belief.
“We can’t be in a situation where there is a desperation just for a result because it goes against the grain of everything we’re trying to build here but we fully understand and I fully understand for a lot of people that is the only measure.”