Tottenham Hotspur coach Juande Ramos has reiterated his determination to keep hold of star striker Dimitar Berbatov.The Bulgarian international is already being linked with a host of clubs, including Chelsea, Manchester United, Real Madrid and AC Milan, since the opening of the transfer window. His agent Emil Dantchev claimed the 26-year-old would like to move to a club which matched his own ambitions. But Ramos, speaking after the 2-1 reversal at Aston Villa, has set his stall out to keep hold of the player. He said: 'Obviously Berbatov's agent is looking to do his business and has made his comments. 'But we are happy because we have the player on a contract, and we plan to keep him.' Ramos has admitted he will look to bring in new defensive blood unless Tottenham can cut out the kind of lapses which cost them both goals against Villa from set pieces. Olof Mellberg opened the scoring from an Ashley Young free-kick and, after Jermain Defoe had equalised, a corner from Gareth Barry was headed in by Martin Laursen for the winner. Ramos said: 'I am not happy because we have come back from a goal down, created chances, and still lost. I think a draw would have been a fairer result. 'But in the past few weeks, we have conceded goals from set-pieces, and it is hard to win matches conceding as many as we do from those sort of positions. 'We are lacking in some defensive departments, and it is something we need to look at. We are paying for lapses. 'We need to find a solution to our defensive problems. If we can't sort the problems out with the players we already have here, we will look outside for other players.' Laursen grabbed his fifth goal of the campaign to ensure Villa came through the festive programme unbeaten and he gave Berbatov few opportunities to shine. It was another strong message from the Danish international who is out of contract next summer, although he has stressed he is happy at Villa. Villa manager Martin O'Neill said: 'Martin Laursen was a colossus tonight - and he has been all season. He was up against one of the best centre-forwards in Europe, and his performance was magnificent. 'He also scores vital goals. This was a big goal for the team, and he is playing like a man possessed. 'But it was a really great effort by all the team. We got a bit tired after going ahead and thought we might have to try and hold onto the lead. 'They got back into it, and we suddenly had to find more energy, and produced a great effort to get the three points.' Villa are now lying sixth in the table, and O'Neill will look to add to his squad during the January transfer window. He said: 'To get 36 points on the board by this stage is really great, and all the players deserve fantastic credit. 'The confidence is high amongst them, and they have tremendous determination. 'But it has been the same players who have kept going, although we have tried to rest them as much as possible. I think we do need to bring in a few players.'