Spurs boss Postecoglou says Champions League no 'golden ticket'
Spurs travel to Aston Villa on Sunday with both clubs vying for fourth spot, which will guarantee a place in Europe's elite competition.
Fifth could also secure Champions League football, but Postecoglou, without naming them, cited Manchester United and Newcastle as examples of teams who have failed to progress after finishing in the top four last season.
"There are a couple of teams who got into the Champions League this year from last year, had a good season," he said on Friday.
"Does that guarantee anything the following season? No.
"What's more important is that come the end of this year, we've got a team that's going to challenge the following year and keep growing. Right now, the most important thing is us, our identity and our football.
"It's not a Willy Wonka golden ticket, you know? It just gets you a year in the Champions League, but if you don't build on that or grow from that, it is meaningless."
Willy Wonka is a fictional character appearing in British author Roald Dahl's children's novel Charlie and the Chocolate Factory.
Postecoglou, in his first season at Tottenham, said his aim was to lay strong foundations.
"If we've improved and make Champions League, it means we've had a decent year," he said.
"But that isn't going to give me any comfort if we're not playing the football that I want to play and we haven't improved in the off-season to make sure we're ready for the next step."