Former world number one Martina Hingis has been banned for two years for failing a doping test, the International Tennis Federation (ITF) announced on Friday.
Hingis tested positive for cocaine on June 29 at Wimbledon and although the Swiss player denied she had taken the drug an independent Anti-Doping Tribunal after a two-day hearing found that she had committed an offence.
The two-year ban is effective from October 1, but the 27-year-old Hingis has alrady announced her retirement from the sport.
The ITF said in a statement: "The Tribunal rejected the suggestion made on behalf of Ms Hingis that there were doubts about the identity and/or integrity of the sample attributed to her.
"It therefore found that she had committed a Doping Offence under Article C.1 of the Programme (presence of a Prohibited Substance in player's sample).
"The Tribunal also rejected Ms Hingis' plea of No (or No Significant) Fault or Negligence, on the basis that no mitigation was possible as it had not been shown how the cocaine entered her system."
Hingis' results from Wimbledon where she reached the third round and subsequent events last year have been wiped out and she has been ordered to repay 129,481 dollars in prize money.
The Swiss player had insisted she was "100 percent innocent" and that this was backed up by a negative result on a hair test, which can show whether or not someone has taken cocaine.
Hingis won 43 WTA singles titles since turning professional just a month before her 14th birthday in 1994, including five Grand Slams.
She first retired in 2003 due to persistent ankle injury problems, but returned to the circuit in 2006, winning three titles in Kolkata, Rome and Tokyo before retiring in November last year following the announcement of her positive drugs test.
Hingis has three weeks to appeal the decision.