Chelsea coach Thomas Tuchel said the reigning European champion was facing an exit at the hands of Real Madrid unless it can regain its focus after a 3-1 home Champions League quarter-final first leg defeat.

Hard on the heels of a 4-1 thrashing by Premier League new boys Brentford on Saturday, also at Stamford Bridge, Tuchel said he was at a loss to explain his team's sudden slump.

"We have to find our level back and I don't know where it is, but ... the first half is a repetition of the second half against Brentford, in a quarter-final against Real Madrid," Tuchel told reporters.

"(We were) so far off our level in absolutely everything what the game demands," he said. "You cannot expect a result from this kind of performance."


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He said Chelsea would lose against Southampton on Saturday if it played as it did in the first half against Real Madrid and said it was alarming to have conceded seven goals in two games, a far cry from the defensive solidity Tuchel introduced on his arrival at the club in January last year.

He said Romelu Lukaku, Chelsea's record signing who only came on as a second-half substitute, had missed a "very important" chance to narrow the deficit with a header when the score was 3-1, but the problems were not just about one or two individuals.

"If we do not get our heads right and our mentality right then we will not win at Southampton and this tie (against Real Madrid) is not alive," he said. "If things change, maybe."