Chelsea have appointed Roberto Di Matteo their permanent manager on a two-year contract.Di Matteo was made interim coach following the sacking of Andre Villas-Boas in March, leading the club to Champions League and FA Cup victories."We all achieved incredible success last season that made history for this great club," said the 42-year-old."Our aim is to continue building on that and I'm already looking forward to the squad's return for pre-season."Former MK Dons and West Brom manager Di Matteo lost just three of his 21 matches in charge, and several of the club's senior players voiced their support for him as permanent boss following the Champions League final success over Bayern Munich and FA Cup final victory over Liverpool."Roberto's quality was clear for all to see when he galvanised the squad last season and helped the club make history, and the owner and board are very pleased he will be continuing his good work," said Chelsea chief executive Ron Gourlay."We all believed he was a young coach with much to offer when we first asked him to take charge and the manner in which he worked with us, the players and all the staff, and the success that followed, made him the clear choice when it came to selecting the person to take us forward in the seasons to come.