Chelsea defender David Luiz believes that he has developed into a better player since leaving Benfica for the Blues in January 2011.The center-back feels that his new surroundings have helped him mature, but stressed that his character has not changed."I moved to another league, to another challenge in another country, so I am older, more responsible and wiser, but the character and the professionalism is still the same," the Brazil international said during a press conference.The 24-year-old then looked ahead to Tuesday's Champions League quarterfinal clash against his former team, and stressed that he is determined to help Chelsea to a good result."I am pleased to return to a place where I was very happy, but the past doesn't matter now," he added. "People know the love I have for Benfica; I will always love this club but I am a professional and will do my job to help my team."It will be a great match played by two great teams. I will meet my friends and that's the way it's going to stay until kick-off, but after that each of them will do their own work."The first leg kicks off at 2:45 p.m. ET on Tuesday at Estadio da Luz.