Mauricio Pochettino expects his Tottenham players to produce a much-improved performance against Sunderland on Sunday.
Pochettino accused Spurs of lacking “passion” and “aggression” after their 2-1 defeat to Monaco, in which defensive errors cost his side dear at Wembley.
They return to White Hart Lane this weekend for the visit of the Black Cats and Pochettino has made clear he will not accept another lacklustre performance.
“When we wait six years, a long time to play Champions League, after 45 minutes you can’t go to the changing room with this feeling,” Pochettino said.
“We had 90,000 people in front of us, waiting for us to play Champions League. The atmosphere was amazing.
“We nearly cried when you hear the song from the Champions League, it’s a dream come true.
“That was difficult. We have time to win games. We have possibility to go to the next round. It’s early days.
“To show more consistency in our behaviour is very important for our future. It’s early in the season but we need to compete much, much better.”
Pochettino was making his own managerial debut in the Champions League and admitted he too may have been at fault.
“I look at myself too. Maybe I didn’t know how to give them motivation to play on Wednesday night in the Champions League,” Pochettino said.
“Maybe I put myself in question too. We share responsibility but we cannot repeat. You can lose, not play well, but never concede two goals how we conceded.”
Tottenham announced earlier on Thursday that 20-year-old Harry Winks had signed a new five-year contract with the club.
Winks follows Christian Eriksen and Eric Dier in extending his deal, with Jan Vertonghen and Erik Lamela expected to follow in the coming weeks.
“I need to say that the club has made a big effort to try to keep all our talents,” Pochettino said.
“It’s fantastic for the club. My feeling is that we need to do more because the club give us a lot of things and very good things and we need to show more like a team. More passion, more desire.”
Despite their disappointing start in Europe, Tottenham remain unbeaten after their opening four games in the Premier League and sit fifth in the table.
Mousa Dembele is likely to make his first domestic appearance of the season on Sunday as he returns from a six-match suspension, but Pochettino said Danny Rose is still a week away from overcoming a hamstring strain.
Kieran Trippier, Moussa Sissoko and Victor Wanyama are also possibilities to come in, with Pochettino admitting he may rest players after their excursions in midweek.
“It’s true that after Wednesday I am thinking about rotating the team a bit,” Pochettino said.
“We’ll see what happens tomorrow when we assess all the players and take the best decision for the team.”
Summer signing Georges-Kevin Nkoudou is unlikely to feature. The 21-year-old, who joined for £11million from Marseille in August, is still adjusting to his new surroundings.
“I think maybe he will be ready to be selected next week, maybe, but not sure,” Pochettino said.
“It is going well. He is very young, he speaks only French, it’s a big problem for him. He is learning quickly but he is still settling into the team.”