Ange Postecoglou said Tottenham lacked "belief and conviction" but promised to find a fix as their Champions League hopes suffered a blow with defeat at Chelsea.
Spurs were beaten 2-0 by Chelsea at Stamford Bridge and are now seven points behind fourth-placed Aston Villa, albeit with a game in hand.
Tottenham have games against Liverpool and title-chasing Manchester City among their remaining fixtures and have now lost three in a row in the Premier League.
"They've lost a little bit of belief and conviction in their football and that's for me to fix," Postecoglou said of his side.