Martina Hingis has revealed she tested positive for cocaine at this year's Wimbledon Championships, but denied taking the drug and has announced her retirement from professional tennis.
A statement released to the media by the 27-year-old Swiss insisted she found the accusations "so horrendous and monstrous I've decided to confront it head on by talking to the press."
Hingis, a five-time Grand Slam champion and former Wimbledon winner, lost in the third round at the All England Club to Laura Granville.
Her statement continued: "My only performance enhancer is the love of the game. When I was informed I had failed my 'A' test following my defeat at Wimbledon I was shocked and appalled.
"I have no desire to spend the next seven years fighting doping officials. I'm frustrated and angry because I believe I'm 100% innocent and accusations such as these don't provide me with the motivation to continue."
Hingis returned to the sport two years ago after a four-year absence because of injuries but acknowledges at 27 she is "too old to realistically play top-class tennis."
Hingis has not played since she suffered a second-round loss to Peng Shuai in the China Open in Beijing on September 19.
Following Hingis' claims, the Sony Ericsson Women's Tour issued a statement. It read: "We have not received any official information regarding the positive doping test result referred to by Martina Hingis in her press conference today, and as a result we are not in a position to comment on the matter.
"However, it is important to remember that in the area of anti-doping, all players are presumed innocent until proven otherwise.
"We have a zero tolerance policy when it comes to doping in sport, and fully support the Tennis Anti-Doping Program.
"The Tennis Anti-Doping program is both rigorous and comprehensive, and is designed to keep our sport clean.
"With respect to her retirement announcement, Martina Hingis is a tremendous champion and a fan favourite the world over.
"In her most recent comeback, she proved again that she can perform at the very highest levels of the game."