The Czech international believes that the Blaugrana must be considered front runners in the tie, but insists the Blues can cause an upset if they can extend their narrow lead.Chelsea goalkeeper Petr Cech believes that Barcelona should be considered favourites in their Champions League semi-final second leg due to their home advantage.Barcelona suffered defeat at Camp Nou to arch rivals Real Madrid on Saturday, and all but conceded the Liga title in the process as they now trail Jose Mourinho’s side by seven points.But the Czech keeper is determined not to underestimate Pep Guardiola\'s side, who will be looking to overturn the narrow 1-0 deficit to remain on the silverware trail.Cech, who has tasted defeat against Barcelona just once in four outings, told reporters: \"They are a great team who know how to handle defeats, they will just want to forget about El Clasico and concentrate on this game.“I think Barcelona are favourites for the game because they are playing at home in front of their fans.\"I think it will be the same type of game as the first leg. A goal for us is going to make a big difference, just like [Andres] Iniesta\'s goal made a difference last time.”This semi-final will be Chelsea\'s sixth in nine years, with the keeper playing in five of them, but the Blues have still failed to get their hands on the coveted trophy, a statistic Cech is aiming to change this year.\"I\'ve been hoping for eight years I would have a chance to win the Champions League,” he continued.“We\'re in the semi-finals again and I hope this will be the year. Many times we\'ve gone close but not managed to do it. If we have a fantastic game [on Tuesday] we have a chance to play the final, but first we need to play 90 minutes or more tomorrow, let\'s see how the game goes, but it\'s too early to talk about the final.\"Encounters between the two sides have been famously controversial, with Drogba\'s dismissal in 2005 and the multiple penalty appeals by Chelsea at Stamford Bridge in 2009. However the 29-year-old believes there will be no such problems with Turkish official Cuneyt Cakir in charge.Cech added: \"A referee can be a big part of game, we\'ve had some great games against Barcelona in the past but there was always controversy, which is a shame as it overshadowed the quality.