The world anti-doping agency won't appeal against the one-month suspension given to five-time Grand Slam champion Iga Swiatek.
She tested positive for the banned substance T-M-Z in an out-of-competition sample last August.
WADA says it accepts the International Tennis Integrity Agency's findings that the failed drugs test was a result of contamination.
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Swiatek was on court earlier beating Germany's Eva Lyse in straight sets to reach the quarter-finals of the Australian Open.
She will be joined by Elena Svitolina, Madison Keys and Emma Navarro who all won their last 16 clashes.
Elsewhere Jannik Sinner is through to the quarters.
The defending champion beat Holger Rune 3-1 to reach the last-eight in Melbourne.
Fellow Italian Lorenzo Sonego is also through, as is American Ben Shelton.
And home favourite Alex de Minaur defeated world number 42, Alex Michelsen in straight sets.
