Postecoglou came out swinging after reaching the final in Norway, striking back strongly at those who have mocked or insulted Spurs' European success.
"It's going to upset a lot of people isn't it," he said, according to the BBC. "The debate's now raging. The latest one is that neither of us will be able to get a trophy if we win — they're just going to take a team photo because we're not worthy."
The Spurs boss dismissed the idea that league form should diminish their achievement.
"Who cares if we're struggling in the league? It's a separate thing. It's got nothing to do with league form. I couldn't care less who's struggling and who's not. I think both us and Manchester United have earned the right to be there."
Given Spurs' season, many have also asked whether winning this trophy would even matter. Postecoglou, however, made apparent its significance.
"I've said all along that this is important. What's happening now is people are fearing that — that it actually might happen, and let's see how we can tear it down somehow... by saying it's been a poor season and we don't deserve this or that, or somehow comparing us to Man Utd.
"Maybe if we had Man Utd's success then maybe I'd have a different view. So of course it's massive. You have to frame it against what this club has been through over the last 15 or 20 years and what the supporters have been through. We've given them some real hope and something to dream about — that we can do something special this year."