Former world number one Martina Hingis has been handed a two-year ban after being found guilty of a doping offence.
Hingis returned to tennis in 2006 after a three-year hiatus
The 27-year-old Swiss star was found to have tested positive for cocaine while competing at Wimbledon last year.
The International Tennis Federation has rejected Hingis's appeal and given her a ban starting on 1 October, 2007.
Hingis, who has since retired from the sport, has also had to forfeit ranking points and prize money from Wimbledon and any subsequent tournaments.
The five-time Grand Slam winner, who returned a positive result from a routine urine sample taken after losing to Laura Granville in the third round of the Championships, had previously insisted she was "100% innocent".
I think she's a nice girl. I was shocked with everyone else. For me, personally, I give her the benefit of the doubt
She claimed that her innocence was backed up by a negative result on a hair test, which can show whether or not someone has taken cocaine.
However, a statement from the ITF said: "Following a two-day hearing in December 2007, an independent anti-doping tribunal found that a sample provided by Ms Hingis on 29 June 2007 at the Wimbledon Championships had tested positive for a metabolite of cocaine.
"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.
"The tribunal also rejected Ms Hingis's 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."
A three-person independent tribunal heard arguments from lawyers representing Hingis and the ITF on 10-11 December.
And in the panel's 46-page decision, the tribunal said: "The force of the case against the player was overwhelming and the tribunal's task was ultimately quite simple."
Hingis retired from tennis when revealing she had tested positive last November.
On Friday her manager, Mario Widmer, said: "Since Martina has retired from competitive sports, it makes no sense for her to challenge the judgment.
"She just isn't going to play any more."
Hingis, who spent three years out of the sport before returning in 2006, won 43 WTA singles titles during her career.
"She's been a great ambassador for the sport, there's no question," said Larry Scott, chief executive of the WTA Tour.
"So it's a sad day for her and for tennis, and I'm very sorry to see her amazing career ending on this note.
"By the same token, we are very vigilant in our efforts to combat doping in sport."
Asked if the positive test tainted Hingis's career, Scott added: "Obviously it's going to be an element of her record and her legacy that I'm sure she hopes wouldn't be there and, I guess, to some degree does take away something from all of her great accomplishments.
"Having said that, her record is so stellar, the warmth that she enjoys from so many fans around the world runs very deep and, over time, I don't think this is going to have a very detrimental effect on her legacy."
And there was support for Hingis from Wimbledon champion Venus Williams, who said: "I like Martina. I think she's a nice girl. I was shocked with everyone else.
"For me, personally, I give her the benefit of the doubt."