There’s really very little to choose between the top 20 players on the WTA Tour at the moment. They’re all capable of making the top ten, and it really is difficult to see who the next long-term No.1 is going to be.

The top four players are separated by less than 400 ranking points, and if one of those wins the US Open in September, they’ll have a good chance of finishing the year as the world’s No.1. All of the top four have a long way to go to become a long-term No.1, but time is on their side, and if they can reduce their weaknesses, one of them could go on to dominate for years to come.

Svetlana Kuznetsova has never been higher than No.2 in the world and is currently No.4 after being knocked out in the fourth round at Wimbledon. After reaching the final of the US Open in 2007 and the quarter-finals of three Tier 1 events last year, her ranking could suffer if she fails to at least better those results this year.

Kuznetsova is an all-rounder, having reached the final of the French Open 2006 and winning the US Open in 2004, and is one of the strongest Tennis players on the tour, able to live with the powerful hitting of Venus and Serena Williams. However, like the Williams sisters, she also has days where her shots are very erratic.

Against the best players in the world, however, she does struggle and only has a winning record against Jelena Jankovic, Venus Williams and Elena Dementieva from the current top 10. And because of the amount of matches she plays and her inability to beat the best in the world, her chances of becoming a long-term No.1 are slim.

Jelena Jankovic is currently No.2 and could have became No.1 if she had defeated Ana Ivanovic in the semi-finals at Roland Garros. But she lost to her compatriot, despite having a 3-1 lead in the final set, hitting 51 unforced errors. Jankovic has a losing record against the other players in the top four, but can boast winning records against the most of the top 10. But it’s her inability to defeat the best in the world at the moment which will prevent her from becoming a long-term No.1.

She’s very much a defensive, counter-punching player and tends to play more matches than anyone else on the tour. Unlike her main rivals, she is yet to reach the final of a Grand Slam in singles, while Ivanovic, Maria Sharapova and Kuznetsova have all won at least one Grand Slam each in the last four years.

Jankovic’s problem is also her serve, preferring to play both the first and second serve with a lot of spin, giving baseline opponents the opportunity to attack her quite often, and she is broken more times in a match than her main rivals. At 23, it will be difficult for her to change her serve dramatically and that will prove to be her downfall against Ivanovic and Sharapova.

Maria Sharapova is the former No.1 and has been ranked in the top 10 since winning Wimbledon back in 2004 – longer than any other current player on the tour. Like many others on the tour, her game is based on power, with a powerful forehand and serve, but her game can collapse if her serve is not working well. She has tried to change it many times over the last two years, but still struggles with it and is prone to hitting a high number of double faults in a short period of time.

Sharapova doesn’t play well on clay, and will do well to ever win the French Open. However, she has already won three other Grand Slams, despite only being 21, and has the ability to win them again. If she can improve her serve and be comfortable with her game when it isn’t working, she’ll stand a good chance of rising back to No.1, but she needs to find a consistency with it to be able to dominate.

Ana Ivanovic is probably the best placed to be a long-term No.1, and is currently No.1 after her victory at the French Open. She was also runner-up at the Australian Open this year and lost in the third round of Wimbledon to China’s Zheng Jie, who was ranked 133 at the time. She is only 20, however, and is continually developing her game. Her mental stability was exposed at Wimbledon and it’s something she will need to work on in the coming months if she is to become the next long-term No.1.

Her serve can be powerful but is largely unreliable getting her first serves in sometimes around 40 per cent, which can cause her problems against aggressive opponents, while she also currently lacks a plan B when her offensive baseline game falters. As a result, she will lose games she should be expected to win because of this weakness. Despite this, Ivanovic has the best game of the top players in the world, and I expect her along with Sharapova to dominate the game for the next five years as the top two players in the world.