Defender Branislav Ivanovic admits Chelsea cannot afford to be caught cold if they are to make it through to the Last 8 of the Champions League.
The Serbia international scored Chelsea's important away goal at the Parc des Princes but has urged his team-mates to keep their feet on the ground despite the "psychological advantage" over Laurent Blanc's side.
"It's a very important goal for the team," Ivanovic told the club's official website.
"We have maybe a little psychological advantage after the game.
"This game was very hard, very difficult, but we played well. I think we deserved a positive result.
"The result is positive for us but we cannot be relaxed, nothing can change in our minds."
The Blues will have an important 1-1 advantage from yesterday's game when they host Paris Saint-Germain at Stamford Bridge on March 11 and the 30-year-old warns that the French giants have enough quality to be dangerous away from home as well.
"[At home] it will be a massive game, a very difficult game. They have great strikers who can score in every game," he said.
"In London they have to score and have fantastic players, so there is no possibility for us to relax one second, and I think we have to play the game in London to win also."
