Chelsea defender David Luiz has warned his side that they will need to play 'intelligently' against Rubin Kazan on Thursday night.
The Russian side have already defeated Atletico Madrid and Levante in earlier rounds, and Luiz has admitted that it is important that they do not concede an away goal at Stamford Bridge.
The 25-year-old told the club's official website: "They've already beaten two good Spanish sides. To arrive at this stage of the tournament, they are obviously a very good team.
"We need to be careful, play an intelligent game and not concede any goals, because that's very important when you play the first leg at home."
The Blues made it through to the last eight with victories over Sparta Prague and Steaua Bucuresti.
