Serbian tennis player Victor Troicki will appeal to sports' highest court to fight his 18-month suspension for failing to provide a blood test.
Troicki says he will trust the Court of Arbitration for Sport to recognize "a clear mistake from the on-site doping control officer."
The 2010 Davis Cup winner says he declined to give blood at the Monte Carlo Masters in April because he felt ill.
Troicki insists the doping control officer advised he could "skip the test if I wrote an explanation letter" to the International Tennis Federation.
The ITF suspended Troicki on Thursday after its tribunal said his explanation "did not constitute compelling justification."
Troicki says of the doping control officer, "once she found out that she didn't follow the procedures, she turned her back on me."