Mauricio Pochettino accused his Tottenham players of lacking fight in Tuesday's 2-1 defeat at Leicester in the Premier League.
Leicester duo Jamie Vardy and Riyad Mahrez scored brilliant first-half goals before Harry Kane halved the deficit late on to leave Spurs with four points from their last five league games.
"They were more aggressive than us. We need to learn and fight from the first minute," the Spurs manager said after the match. "If you don't fight in the Premier League the quality gap is even.
"You cannot afford no fight. You cannot win games. If you don't compete in the Premier League you are going to struggle.
"It's difficult to analyse the game. We start so sloppy. The performance in first half disappointed us a lot. First you must compete and fight and be focused and then quality will appear.
"Leicester showed more than us today. Ready to fight in the first half. Even if the game was open and we had chances to score and stay in the game we were poor and this is disappointing and frustrating. It's difficult to know why. Not about tactics or systems or selections. It's about the collective. The collective performance was so poor.
"Second half we competed, we fight, and in the end the game finished 2-2 or 2-3 we deserved it. We weren't clinical in front of the goal. We had easy chances to score."
Erik Lamela came off the bench for his first appearance in 13 months and assisted Kane with his third touch.
"Erik has different qualities and it's helpful for the future to have him back," was all Pochettino said of the Argentine winger.
But another substitute, Fernando Llorente, missed from two yards at 2-1 and Pochettino admitted the Spaniard's confidence is low.
"Of course, he needs to build confidence. It was a chance to score, so clear but we need to accept that. We need to be calm and trust and work hard and be ready for the next game," Pochettino said.