Dominic Solanke’s 43rd minute penalty was enough to send Tottenham through to the semi-final against Norwegian side Bodo/Glimt.
Spurs have struggled domestically, sitting in 15th in the Premier League table with just 37 points from their 32 games but have found some solace in Europe.
Winning the Europa League would mean the Tottenham Hotspur stadium will host Champions League football next season, regardless of their league position.
Speaking to the press ahead of their game with Nottingham Forest on Monday, the Australian remains hopeful his side can salvage something from their season.
Ange Postecoglu and Tottenham fighting until the end
"At times it can, yeah," he said. "Depending on the result and more importantly the context in which it is made.
"It’s easy to sit here and say Thursday night is a pivotal moment, but it won’t be a pivotal moment if we don’t back it up in the semi.
"That’s when you’ll find out whether it was and if you do a season review DVD – do they still do DVDs? – you might go ‘that was the turning point’, but you only do that at the end.
"But do I think Thursday was significant? Yes, I do. For a number of reasons. We overcame a real difficult opponent. We deserved to go through.
"There was no luck about it. Over two legs we were the stronger team, we did it in a real convincing manner and just the prospect of being in a semi-final means you’re two games away from being in a European final.
"That is hugely incentivising so it may be that was the pivotal game, but we won’t know that."