Petr Cech has admitted his disappointment at how Paris Saint Germain star Javier Pastore managed to bypass his Chelsea teammates to score the third goal of the game in the Blues' 3-1 defeat against the Ligue 1 side.
Chelsea must now make up a two-goal deficit next week at Stamford Bridge to qualify for the Champions League semi-final after the Argentinian struck in injury time.
Cech believes Chelsea had back luck with the own-goal scored by David Luiz to make the scores 2-1 to PSG but admits they could have done more to stop Pastore.
"Sometimes that is the way it is. You need to control every detail and we were a bit unlucky. The second goal goes through about 15 people and nobody touches it and then it hits David Luiz and goes in, and it was one of those games, but the most disappointing was the last goal because we were all there, ready, and Pastore managed to go through from there and managed to squeeze it through me as well," Cech told Chelsea's official website.
Manager Jose Mourinho also criticised his players for gifting Pastore the third goal.
"We scored in our own goal, and the third goal ... it's a joke. Not a goal, a joke. Gary Cahill said it was sloppy but I say it was ridiculous. It was Pastore and us," Mourinho said.
Meanwhile, Cech believes Chelsea can still progress to the semi-final if they manage not to concede more goals at Stamford Bridge in the second-leg.
"Win 2-0 and you are through so you have to make sure you don't concede at home and take all your chances to score goals and then you can progress," he said.
"We have put ourselves in a difficult position but while everything is still possible we cannot say the tie is done. It is not 6-0 or 4-1 or 5-1. A 2-0 is possible to win the game at home and it is up to us."