In just over two weeks, we could see history being made by a sportswoman who can lay claim to being not merely the greatest female tennis player of all time, but the greatest tennis player of all time, full stop. Serena Williams goes into the US Open, which begins on Monday, having already won the first three grand slams of 2015. If the 33 year-old triumphs in New York, she will be the first player to have won the calendar grand slam since 1988 when Steffi Graf achieved this feat.

In fact, Williams already currently holds all four grand slam titles having also won the 2014 US Open- she calls this the ‘Serena Slam’ and is the second time that she has held all four major titles simultaneously, the first time, remarkably, was twelve years ago. The American has won 21 grand slam titles, only Graf and Margaret Court have more with 22 and 24 respectively and with Williams showing no signs of slowing down, it seems likely, inevitable even, that she will surpass both.

Williams’ story is well documented; along with her sister, Venus, they grew up in Compton, a rough area of California and were taught to play tennis by their father on dilapidated old courts. At times the girls would have to take cover to avoid getting hit by stray gunfire from the gang violence that gripped the city. Williams won her first grand slam title- the US Open- at the age of 17 and from then on, she was on the path to greatness. Her statistics are incredible; on top of her grand slam record, she has spent 255 weeks as world number one, has won 69 WTA titles and has accumulated over $73 million in prize money so her story appears to be a ready-made fairytale.

Yet for all of Williams’ indisputable greatness, she is not revered in quite the same way that so many great champions are. Williams’ achievements are as incredible as Tiger Woods’, Usain Bolt’s and Roger Federer’s but she seems to be somewhat less appreciated and she is certainly not universally loved. There are a variety of reasons for this; some of it may be sexism, some of it may be racism but this still does not give a full explanation. Williams has a more impressive cv than Roger Federer yet has never been held in quite the same regard as the Swiss. Admittedly though, no one is revered in quite the manner of Federer- he is, after all, a man who can walk onto court wearing a cream suit and still avoid ridicule.

Williams unashamedly shows her emotions and that, it seems, turns some people off. She has not avoided controversy either- she has been accused of fixing the results of matches against her sister, she has been fined for swearing on court and for threatening a line-judge but her offences are no worse than those of many other players. Williams can be surly in press conferences and she can come across as false at times too but she also has a personality and a charisma of which few of her fellow players can boast. Williams changed the game of tennis forever with her athleticism and her physicality yet this has also attracted criticism- the American has been described time and time again as manly because being fit and muscular is not really allowed if you are a woman. Despite having amassed such an incredible haul of titles, she is still not the highest earning female player; last year, Maria Sharapova earned $29 million to Williams’ $24 million. It seems that many companies still prefer to have the blonde, white girl advertising their products.

Even some of Williams’ direct rivals agree that the American is undervalued; Ana Ivanovic, a fellow grand slam champion, said that she hopes Williams wins the US Open title before adding: “I just think we're lucky to have someone like Serena in our sport. She's worked really hard and been at the top for so long. She doesn't get enough credit for what she has achieved- everyone talks only about men's tennis, but to have someone like Serena, it's very fortunate.”

Williams seems largely unconcerned with the public’s opinion of her though. She is aiming to become the indisputable greatest tennis player of all time and there is every chance that by this time next year, she will be. The pressure on her at the US Open will be immense and she has not always coped well with pressure but Williams has lost only two matches all year and if she gets through the early rounds when she is most vulnerable, it would be a brave person to bet against her. Williams must have, at most, only a few more years of her career remaining. The legendary Chris Evert described her as ‘‘a phenomenon that comes around once every hundred years.” She is almost certainly right- we may never see a tennis player of Williams’ like again, we should make the most of it while we can.