Mauricio Pochettino thinks it could take another five years before Tottenham are ready to challenge for the Premier League title if Saturday's result at Burnley is anything to go by.
Spurs could have ended the weekend just three points off leaders Liverpool if they had beaten the Clarets, but they fell to a damaging 2-1 defeat.
Pochettino's frustration at his side's limp display boiled over after the game as he clashed with referee Mike Dean, earning him a Football Association charge for improper conduct which he will not contest.
The Argentinian had explicitly warned his side before the match that it was their most important of the season, but they fell flat, much like they did at Watford earlier in the season in the wake of a standout win at Manchester United.
Pochettino, who has been Spurs boss for almost five years, reckons it could take the same time again to change the mentality at the club.
"The example is Watford," he said speaking ahead of a Premier League trip to Chelsea. "One-nil [up], and then in the last 20 minutes we threw away the game, because of us, not because of Watford.
"If you watch the game again you know that is what happened, and my worry is what happened and to change that is not only five-year work, maybe it is 10-year work to change that thing that happened here."
Pochettino believes that if his side had any chance of winning the title then they have to win games like Saturday's against Burnley.
"To be a real contender in this type of game, playing well or not playing well, it is a must-win game. And it is unacceptable to lose," he said.
"If you lose you cannot after say 'No, we are a real contender, in the last 10 or 12 games you must be strong and you have to dominate and show you are a real contender'.
"We showed on Saturday that we are a good team yes, we have good quality yes, but it's not enough to win a title like the Premier League and that is the reality.
"I think you think the same and the players think the same and everyone thinks the same.
"If you're not going to be able to beat Burnley playing for the title I think it's impossible to think that you are going to win the title.
"Maybe you might win afterwards but because another loses the opportunity to win, not because you push to win."
With games against Chelsea, Arsenal and Borussia Dortmund all coming up in the next six days, Pochettino said his side did not have the desire against the Clarets.
"That is what worried me," he added. "Of course it's easy to go to Chelsea and be motivated to play, and play again Arsenal or Dortmund, it's easy and you don't need a manager that tells you 'Oh, you need to be motivated, excited to play', because that's normal.
"But you play for the Premier League for the big game like Burnley.
"It's dry the pitch? It's dry, it's normal. The changing room or the dressing room is not so big like at Wembley? Of course it's not.
"But come on, you need to respect and the way you need to respect is to go there and show more ambition, show more attitude, show more capacity to fight."