LAUSANNE (AFP) - Serbia's Viktor Troicki has turned to the Court of Arbitration for Sport (CAS) in his drive to overturn an 18-month doping ban handed down by the International Tennis Federation (ITF), the tribunal said on Tuesday.

The former world No.12, a Davis Cup winner in 2010, should learn within four months whether his name has been cleared or not, the CAS said.

It underlined that Troicki had not filed a request for a stay of his suspension pending a ruling, meaning that he cannot return to competition until the court decides on his fate.

The ITF announced on July 26 that Troicki had been banned till Jan 24, 2015.

The sanction came after he was found guilty of failing to provide a blood sample during a drug test at the Monte Carlo Masters in April.

The 27-year-old maintained that anti-doping officials at the tournament had told him his urine sample was sufficient, given that he did not feel well enough to provide a blood sample.

But that failure constituted a dope test failure, said the ITF, despite the player's insistence that he was under stress at the time.