The 24-year-old Spain international, who has netted 12 goals for the Blues since signing from Valencia last summer, beat off competition from Branislav Ivanovic and Ramires to scoop the award voted for by fans.
“I just have to say thank you,” Mata told Chelsea TV. “It is my first season here so it is even more special for me and I want to say thank you to my team-mates and the staff and all the people who voted for me. I am realising what it means to play for Chelsea.
“I didn’t expect it but I have had the opportunity to play a lot of games and enjoy English football. It has been an amazing season as we won the FA Cup in my first year and we have the chance to win the Champions League. It is history for this club and I will never forget this season.
“My debut was a dream debut with a goal and a win against Norwich and the FA Cup final is the other highlight.”
“Here the games are more box-to-box and I had to adapt physically but I think I improved a lot and I wish next season will be better for us and for me as well.”
Meanwhile, Ramires won the Goal of the Season award for the second year running for his chip against Barcelona in the Champions League semi-final second leg at Camp Nou last month.
He said: “It is really special to receive this in my second year here and I hope to win it again.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news