• Spurs struggling without a manager after successive defeats
• 'It's not that bad … we know we can achieve big things'

Mousa Dembélé maintains that Tottenham Hotspur can still achieve "big things" this season, despite the crisis that has gripped the club and which necessitated the sacking of the manager, André Villas-Boas, on Monday.

Tottenham were knocked out of the Capital One Cup on Wednesday under the caretaker charge of Tim Sherwood, losing 2-1 at home to West Ham United, a result that followed Sunday's 5-0 hammering by Liverpool, also at White Hart Lane. The team have been erratic since they lost 3-0 at home to West Ham in the Premier League on 6 October. But Dembélé said the players had spoken as a group about what needed to be done and that the situation was not as bleak as it might appear. Tottenham are only five points behind fourth-placed Manchester City and they continue to believe that they can recover to qualify for the Champions League.

"We don't have to be negative; it is not that bad," Dembélé said. "We expect so much of ourselves and we know that we can achieve big things. When it doesn't happen, you're very disappointed. In the last few games, we could have done much better. We have to stay with the same motivation."

Villas-Boas did not always start with Dembélé in the Premier League, to the midfielder's disappointment. But Dembélé said that he and his team-mates felt bad about his dismissal.

"I think everyone feels guilty and that's a normal thing," Dembélé said. "It's a team sport. It's not one guy that's responsible, everyone is responsible. Everyone has a piece [of what went wrong]. Everybody feels responsible. We have talked among the team already and we said to each other: 'Now let's do it. It's everybody's fault. We are one team, all together.'"

Sherwood said after the West Ham game he was not certain whether he would be in charge for Sunday's visit to Southampton but he will be and he is likely to remain in position for the club's fixtures over the Christmas and new year period.

He will be without Andros Townsend, after the winger damaged his hamstring against West Ham. He has undergone initial tests and the club fear that he could be out for four weeks.

"It's difficult to say right now [whether Sherwood should get the job permanently] because it's just happened recently," Dembélé said. "I don't know Tim that well. But the way he talks and his manner ... I think everyone likes this. Everybody is very positive about this. It's difficult to have one day and change everything. It takes time but I think we've already started to play quite well [against West Ham.]"