Serbia’s Viktor Troicki has been banned for 18 months for failing to provide a blood sample during an anti-doping test before the Monte Carlo Masters in April.

The International Tennis Federation said in a statement on Thursday that Troicki had provided a urine sample, but not a blood sample, and therefore had violated anti-doping rules.

Troicki told a news conference on Thursday that 'this is the toughest moment of my career and of my life.'

'I am innocent,' he said. 'I have never ever taken any prohibited substance or ever thought of doing so. I did not lie and this really hurts.'

Troicki had told an independent tribunal that he had been assured by the Doping Control Officer at the event that it would be acceptable not to provide blood as he had been feeling unwell that day, the ITF said.

'Accordingly, the tribunal determined that Troicki’s actions constituted a failure and a refusal to provide a blood sample, and that his explanation for not doing so did not constitute compelling justification...'

In addition to the suspension, the ITF said Troicki’s results at the Monte Carlo Masters would be erased, and that he would forfeit both ATP ranking points and prize money from the event.