It used to be the case that Caroline Wozniacki could never win. When she won a match it was because the other player lost it; when she won a tournament it was because better players hadn’t entered; and when she was world number one, it didn’t actually mean she was the best – only the one who was prepared to sacrifice everything else, including her chance to win a grand slam, to top the rankings.

But now Wozniacki simply can’t win. The media no longer criticise her for winning badly, only losing badly. So far this year, she’s barely won more games that she’s lost, and in the build-up to the French Open, which starts this coming Monday at Roland Garros, she has been knocked out in the first round of three successive tournaments. Take away her appearance in the final of Indian Wells in March, and 2013 has mainly consisted of a series of early exits against players she was seeded to beat.

It’s a worrying trend for a player who has always struggled against the top players, but consistently beaten the small-fry. While her world ranking remains strong at number nine – she didn’t have a particularly good first four and a half months in 2012 either, while many of her rivals are failing to defend the points they accumulated back then – eight more months of this kind of form will see her fall out of the top 32.

A high ranking is important for a number of reasons. On the court, it has helped Wozniacki to avoid the top players until the latter rounds, sometimes providing byes.
And off the court, it has helped bring her worldwide fame and attention. In 2010 and 2011, Wozniacki spent 67 non-consecutive weeks as the world number one and accordingly became one of the biggest names in the game. Last year, she finished number four on the Forbes Rich List for the world’s highest-paid female athletes with earnings of $13.7 million, of which 75 percent came from endorsements from sponsors like Adidas, Yonex, Proactiv, Rolex, Sony Ericsson, Compeed, Danske Invest, Oriflame, Turkish Airlines and e-Boks.

And her brand shows no sign of decreasing in value just because she’s slipped a few places in the rankings. With an equally famous boyfriend, the world number two golfer Rory McIlroy, and no scruples about cashing in on her looks, the young Dane, who is a resident of Monaco for tax reasons, has more tricks up her sleeve than just a strong two-handed backhand.

Last September, she launched her own underwear range – proving she has a good body for business as well as a head, she did the modelling herself. And last week, it was announced that Wozniacki the businesswoman has signed a deal with niche social network EFactor Corp, the world’s largest entrepreneurial community, which will provide her with all the marketing assistance that she needs to make her brand as successful as possible.

Adrie Reinders, the chief executive of EFactor, explained in the official press release that his company’s interest lies more in Wozniacki the businesswoman than Wozniacki the player. “Caroline is a stand-alone business and the CEO of her personal brand,” he said. “The success she has achieved on the court has allowed her to create a sustainable business off the court.”

However, there are some within the game who feel she must concentrate more on Wozniacki the player than Wozniacki the businesswoman. Christian W Larsen, a former tennis coach and player who is now the editor of Det Fri Aktuelt, believes that she needs to forget about the endorsements and take a six-month sabbatical. “She needs to find out what she really wants,” he told Sporten.dk. While Anders Haahr Rasmussen, a tennis commentator on Eurosport who wrote a book about Wozniacki called ‘One ball at a time’, agreed, suggesting she needs to learn from the career of the Swedish multiple grand slam winner Mads Wilander, who struggled after winning the French Open as a 17-year-old in 1980. “He took a few years off and returned with a better perspective of what tennis really meant to him,” he told Sporten.dk. “Wozniacki appears to be going through a similar struggle.” Looking ahead to Roland Garros, Wozniacki is rated a 100/1 chance (Ladbroke’s) to conquer the clay and win her first grand slam title. With only one win on clay all year, and none in three tournaments in Europe (Stuttgart, Madrid and Italy), she continues to struggle on a slow surface that normally suits players with a predominantly defensive game. And as Bojana Jovanovski, Ksenia Pervak, Qiang Wang, Garbine Muguruza, Stefanie Voegele and Carla Suarez Navarro – just some of the lesser players who have beaten her this year – will testify, she is clearly lacking in confidence. These days any player with a few shots in their armoury knows that all they have to do is muster more winners than unforced errors to send Little Miss Sunshine packing.

Then again, it’s not like we didn’t see this fall coming. The media, and most of the public to be fair, have always known she just isn’t that good. She might have been world number one, but Maria Sharapova and Serena Williams were mainly injured, and Belgian players Justine Henin and Kim Clijsters couldn’t make up their mind whether they were aspiring or retiring.

It seems a long time since Wozniacki, then aged 19, made the final of the 2009 US Open, and in her last five grand slams, she has only made the quarter-finals once (2012 Australian Open).

A survey conducted by TV2.dk of several international tennis journalists found none who thought the Dane could realistically reach the last four at Roland Garros – with most predicting an exit in the third round, depending on the draw, which is due out on Friday.

Given her recent form, that might be a little generous.