Victor Troicki has announced that he will appeal against his 18-month ban for breaking doping rules.
The world number 53 was given the punishment for failing to provide a blood sample as part of the sport's in-competition testing program during the Monte Carlo Masters in April.
In a statement on his website, the Serbian said: "I put my trust in the Court of Arbitration of Sports in Lausanne, I really hope they will look for the truth and find it, which is only one. I am destroyed and exhausted. [World number one Novak Djokovic] said that he is sure it will end good because I am innocent, and that ATP should really back me up with this.
"I gave the urine samples and told the doctor I was feeling really bad and I believed that drawing blood would make me feel even worse. I always feel awful when I need to draw blood and that day I was scared I would end up in hospital.
"The doctor in charge of the testing told me that I looked very pale and ill, and that I could skip the test if I wrote an explanation letter to ITF about it. She dictated the letter to me and let me go without giving blood. She was very helpful and understanding."
Troicki lost to Jarkko Nieminen in the first round of the tournament.