Tottenham's Champions League curtain-raiser against Borussia Dortmund at Wembley is "like a final", according to manager Mauricio Pochettino.
The Spurs boss said the opening match in Group H between the two sides expected to contest second place behind reigning champions Real Madrid would demonstrate whether his team were finally ready to shine on the European stage.
Spurs struggled when playing in this competition at Wembley last season and failed to recover from what was then a shock 2-1 loss to eventual semi-finalists Monaco in their first group fixture.
"Tomorrow is such an important game," said Pochettino. "To start well in the competition and get three points will be key to the future.
"It's true that in theory [Group H will finish] Real Madrid first; then Dortmund, Tottenham and Apoel to compete to be second. That is in theory, but football is not theory.
"It is about trying to play and trying to win. Our ambition is to try to win every game. Tomorrow we need to be focused. It is the most important game. It is like a final. We need to show that we are competitive and we can go ahead and be in the next stage."
This campaign marks the first time Tottenham will play in the Champions League for a second consecutive year, following last season's early exit into the Europa League.
Pochettino said his side have learned from the disappointing campaign but now have less excuse for failure.
"The experience of last season is important," said the Argentinian.
"We know very well what the competition demands from you and I think that is so important, that experience from last season.
"It was a very painful experience because we could not be at the level we should have been but today, it's not an excuse. We know that tomorrow will be very tough. We need to be ready to compete at a higher level."