Chelsea manager Andre Villas-Boas has insisted that his side must remain strong after their 2-1 defeat in the Champions League to Bayer Leverkusen.

Manuel Friedrich's late goal in Germany condemned the Blues to their fourth defeat in five games.

The loss also means that the Premier League side will need to earn a point against Valencia in their final group stage game to secure their place in the last 16.

"It's tough for the English clubs in the Champions League at the moment but we have to put on a brave face," said Villas-Boas. "We were compact and disciplined against set-plays - right until the last moment.

"There are no perfect organisations. One small detail makes the whole difference. But we are still in front of Valencia and expect Leverkusen to do their job. We can go through."

Chelsea next host Wolverhampton Wanderers in the Premier League on Saturday.