David Luiz admits Chelsea put in a 'shocking' performance as they went down 2-1 to Shakhtar Donetsk in the UEFA Champions League.
The Blues never got out of the blocks in the Ukraine against a side brimming with confidence after going 11 months unbeaten.
Chelsea are the current holders of the European crown, but they will need to raise their game considerably if they are to defend that title at Wembley Stadium in May.
Luiz admits as much, with the Brazilian centre-half at a loss to explain why Roberto Di Matteo's side were so sluggish on Tuesday night.
"Yes, it was a shocking performance because we want to win games in the Champions League," he told Sky Sports.
"It was a difficult game and in the second half Shakhtar deserved the win.
"The Shakhtar players played so intelligently. They didn't give us opportunities to win the game, so it was only the last 15 minutes that we were pressing.
"Congratulations to Shakhtar, they deserved to win the game. That's it."
Chelsea, who left Donetsk with only a late consolation from Oscar to show for their efforts, are next in action against Manchester United in the Premier League on Sunday.
Luiz admits that game now needs to be the focus, with there little point in dwelling on the events of the past.
He added: "Sometimes you cannot play well. Tonight it was that.
"We need to now think about the next game because Chelsea is a big club and needs to win."