So it turns out that being one of the planet's most successful athletes, world No.1 and arguably the best female tennis player to have lived, does not exempt one from derogatory comments about one's appearance.

Last week, Shamil Tarpischev, the president of Russia's tennis federation, appeared on a late-night Russian talk show and commented on how tough a task it must be for the female players on tour to defeat Serena Williams as well as her sister, Venus. He called them "the Williams brothers". He went on to call the sisters scary, saying: "It's frightening when you look at them."

Tarpischev dug himself into an even deeper hole trying to explain his comments. He claimed that the show he was appearing on was "humorous" before adding: "I'm sorry that the joke was taken out of context and attracted so much attention."

So, a high-powered individual referring to two of the best female players of their generation - and two of the most marketable athletes in the game - as 'male', is meant to be funny? Yeah, hilarious.

Serena, understandably, did not appreciate Tarpischev's supposed joke, and responded to the Russian's comments by saying: "I thought they were very insensitive and extremely sexist, as well as racist at the same time. In this day and age - 2014 - for someone with his power, it's really unacceptable to make such bullying remarks."

Players past and present came to the Williams' defence, with Maria Sharapova calling Tarpischev's comments disrespectful and Martina Navratilova stating that such behaviour cannot be tolerated.

The Women's Tennis Association did not see the funny side either, imposing a fine of $25,000 on Tarpischev and suspending him from involvement on the tour for one year. "The statements made by Shamil Tarpischev with respect to two of the greatest athletes in the history of women's tennis are insulting, demeaning and have absolutely no place in our sport," said Stacey Allaster,

WTA chief executive.

"Serena and Venus Williams are champions on and off the court, outstanding human beings and amazing role models who have done so much to inspire women and girls around the world to achieve their dreams."

She added: "His [Tarpischev's] reinstatement will be dependent upon good behaviour. Mr Tarpischev owes Venus and Serena Williams a personal apology, as well as other players and tennis fans everywhere, a public apology."

The reaction of the WTA was almost faultless: swift, non-negotiable and assertive. The organisation left no one in any doubt that disparaging, sexist and demeaning remarks such as Tarpischev's are not acceptable in any context.

Not all among tennis's ruling bodies have been quite as emphatic in their rebuke. The International Tennis Federation released a statement revealing that they were "disappointed" with Tarpischev's comments but they were taking no tangible action against him. Navratilova described the ITF's silence as "deafening".

While the response of the majority of observers to Tarpischev's slur has been encouraging, this is just another example of female athletes being judged on their appearance rather than their performance. It is simply further evidence of sportswomen being forced to endure these long-standing, pernicious attitudes to which their male counterparts are not subjected.

Serena Williams, in particular, has suffered streams of abuse over her appearance, being called everything from fat to overly-muscular. Yet the value of the presence of the Williams sisters on the tennis circuit is incalculable. To say there have been few black tennis players in the history of the game would be an understatement. There are still very few black tennis players, men or women, who have ascended to the top of their sport.

Serena described Tarpischev's comments as "racist". While they are far more overtly sexist than racist, there does appear to be a hint of racism there. His remarks lean towards the traditional stereotypes that black women are scary and masculine.

Throughout their distinguished careers, the Williams sisters have become role models for young black girls around the world. They have proved that, in spite of the racism that is still prevalent in many spheres, black women can be successful.

At the root of Tarpischev's attitude, though, is plain, old-fashioned sexism. Attitudes such as his propagate the myth that women should not be athletic or muscular or competitive, and that to move one's sport on as the Williams sisters have unquestionably done with their superior fitness, speed and strength has been a bad thing, when it has, in fact, been revolutionary.

What the Williams sisters have proved over the past 15 years or so, since their emergence on to the world stage, is that being an athlete at the peak of one's powers is something to be proud of and something that children should aspire to.

The WTA's response to the comments illustrates that the organisation realises just how valuable the sisters are to tennis, and to sport in general. Tarpischev's words demonstrate that, despite the dimininshing influence of these anachronistic attitudes towards sportswomen, they do, sad to say, still exist.