The north London club are currently just six points behind league leaders Liverpool, but their title hopes suffered a huge blow in defeat to Burnley at the weekend.
They lost 2-1 to Sean Dyche’s side at Turf Moor despite welcoming back star man Harry Kane.
It was a brilliant opportunity for Spurs to close the gap to Liverpool, especially as the Reds ended up drawing 0-0 with Manchester United.
However, Spurs couldn’t muster another goal and eventually succumbed to defeat against the Clarets, with their manager insisting his players only have themselves to blame.
“My worry is what happened and to change that is not only five years work,” Pochettino said. “Maybe it is 10 years work to change that thing that happened.
“To be a real contender, playing well or not playing well, it is a must-win game. And it is unacceptable to lose.
“You need to show like a team that you are fighting for big things and to be honest, I am so frustrated because we didn’t show more attitude than Burnley.
“We didn’t show more energy than Burnley, we didn’t show more ambition than them, fighting for the Premier League. That is what worried me.
““We didn’t show more energy than Burnley.”Mauricio Pochettino
“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 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.”
Spurs face another tricky test next as they take on Chelsea in the Premier League on Wednesday night.