Ukrainian Dayana Yastremska's appeal to the Court of Arbitration for Sport (CAS) for her provisional doping suspension to be lifted has been dismissed once again, the International Tennis Federation (ITF) said on Friday.
Yastremska, 20, was suspended in January after the World Anti-Doping Agency (WADA) found a banned substance in an out-of-competition urine sample she submitted.
She has denied using performance-enhancing drugs and said the positive test was the result of a "contamination event".
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Since receiving the provisional suspension, Yastremska has filed several appeals but failed at every attempt.
The ITF had denied Yastremska's initial application to have the suspension lifted, prompting the world number 31 to approach CAS which dismissed her appeal in February.
That decision left her ineligible to participate at the Australian Open despite travelling to Melbourne for the event.
Yastremska's second application for her suspension to be lifted was also denied by an independent tribunal last month.
With CAS rejecting Yastremska's latest appeal, the ITF said she remains ineligible to compete, pending the final resolution of her case.
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