Cesc Fabregas perks up when he talks about the killer instinct , the ruthless streak that all teams develop at the start of a success story . On instant recall is the World Cup in 2010 , when Spain turned to every available resource to reach the final after titanic struggles against Paraguay in the last eight and Germany in the semi-final . Fabregas was part of that team , realising a boyhood dream when he lifted the most famous trophy in world football with one of the best sides in history . Cesc Fabregas urged his team-mates to develop a killer instinct in order to progress past Paris Saint-Germain . Fabregas makes his way on to Chelsea 's training pitch with John Terry , Cesar Azpilicueta and Gary Cahill . The Spanish midfielder jokingly wrestles with Didier Drogba and Terry during Tuesday 's training session . Chelsea ’ s dressing room is developing a winning mentality again , lifting their first trophy together at Wembley 10 days ago when Jose Mourinho ’ s team won the Capital One Cup . It has given them belief . ‘ When you unlock the mental fear of the quarter-final , which is what we did with the national team , we felt we could become champions , ’ said Fabregas . ‘ Once we were champions we were unstoppable , but you have to take this fear out and take it away . We have to believe we are the best . ‘ We have to be ready mentally to win every situation because this game will not be a walk in the park. ’ He was talking about Wednesday evening ’ s opponents Paris Saint-Germain , a tough nut to crack in the Champions League as Laurent Blanc ’ s team arrive in London protecting an unbeaten run that stretches back to January 10 . Fabregas likes what he sees in the Chelsea dressing room and yet his experience , after nearly 500 appearances for club and country , tells him there is still room for improvement . ‘ If there is one thing missing it is killing teams , ’ he admitted . ‘ Sometimes we don ’ t kill them when we have the chance . ‘ When we score one we have to score more and more . That ’ s the only way we can really improve , developing that killer instinct. ’ Chelsea can smother teams , a tactic Jose Mourinho has refined quite brilliantly over the years with Porto , Chelsea , Inter Milan and Real Madrid . Fabregas is eager to please his manager as he learns a new , more disciplined position alongside Nemanja Matic in the centre of midfield . Chelsea are hoping to build on their recent Capital One Cup triumph over Tottenham . Fabregas ( right ) is enjoying working under Chelsea boss Jose Mourinho ( second left ) since signing . Fabregas loves his football at Chelsea , cheerfully claiming that he is at the top of his game following his move from Barcelona last summer . ‘ I have to be more disciplined and you don ’ t see me in the box so much , ’ he added . ‘ I am more positional , always behind the ball , always finding solutions for the other players and controlling the tempo . ‘ If you asked me 12 months ago whether I would work with Jose I would have said “ no ” , but you can never say never . ‘ Working with Jose , it has been really good so far , but I expected that . I knew he was a great personality and I knew coming to Chelsea , a big club with a big manager , that I would work a lot . I have enjoyed this the most in my career . We need to keep growing as a team . ‘ I will give everything for Chelsea to win the Champions League , but it doesn ’ t mean I can ’ t sleep at night . ‘ For every football player they want to win the World Cup and the Champions League. ’ Mourinho has revealed his admiration for Fabregas , pictured in 2006 , during his younger years at Arsenal . Mourinho admired the Spain midfielder from afar when he was running the show for Arsenal . Fabregas played in the 2006 Champions League final , alongside Gilberto Silva when Arsenal were beaten by Barcelona after extra time in the Stade de France . He was in the centre of midfield that night , putting in an arduous shift in the boiler room because Arsenal were down to 10 after the dismissal of goalkeeper Jens Lehmann . A year later he faced Chelsea in the Carling Cup final , unlucky to lose after a battle royal with some players of pedigree in Mourinho ’ s side . ‘ As a kid he played against our midfield in the League Cup final in 2007 and we had ( Michael ) Essien , ( Claude ) Makelele , ( Frank ) Lampard and ( Michael ) Ballack , and he was playing fantastic football , ’ said Mourinho . ‘ I never felt he could work with me because when I was at Chelsea he was at Arsenal and when I was at Real Madrid he was at Barcelona . So it was quite unexpected for me that he wanted to come to Chelsea. ’ Now that he is here , they wouldn ’ t be without him . Visit Squawka for more Champions League stats and facts .
Cesc Fabregas believes his side must learn how to finish off games . Jose Mourinho go into second leg following 1-1 draw at Parc des Princes . Fabregas is happy to be playing under Jose Mourinho boss Chelsea .