Thomas Frank hit back at those who booed goalkeeper Guglielmo Vicario and claimed they were not 'true Tottenham fans' after losing at home to Fulham.
Vicario's mistake led to a second goal conceded inside the first six minutes and he was a target for jeers and ironic cheers from some sections of the home crowd.
'When you're down 2-0 after six minutes, there is a mountain to climb,' said Frank. 'The classic thing, when you're in a bad spell, everything seems to go against you as well. The first was a deflected shot, the second is a mistake from Vic.
'I didn't like that our fans booed at him straight after. For me that's unacceptable. They can't be true Tottenham fans because everyone supports each other when you're on the pitch and we do everything we can to perform.
'I'm fine with them booing after the match, no problem, but not during. To turn things around we need to do it together.'
Vicario apologised for his mistake and said: 'It's part of football. I'm a big man. We cannot be influenced by the situation in the stands.
'The fans have the right to say what they think. It's up to us to stay calm and focused on ourselves.'
Kenny Tete and Harry Wilson scored Fulham's goals. Mohamed Kudus pulled one back as Spurs improved in second half but they could not find an equaliser and have now won only three of their last 13 games.
'It was an emotional performance in the second half, and that's quite normal,' said Frank. 'We know that we badly want to win at home, so when it's not going your way, it is hard.
'That's why you need to stick to the plan, be cool and not stress. It is easier said than done.'
For Fulham, it was a first away win of the season. 'The first half was top,' said boss Marco Silva.
'We should have scored more, should have killed the game. That was the reality. The best team won.'