After the shock of Justine Henin's retirement from women's tennis, the WTA No.1 ranking would appear to be up for grabs.

Henin dominated the sport over the years and, although there were brief spells where the Williams sisters, Kim Clijsters, Amelie Mauresmo and Maria Sharapova all took her crown as world No.1, Henin was the best at what she did. Henin voluntarily conceded her world raking immediately on retirement and Sharapova took over the position after a consistent start to year with victory in the Australian Open.

Sharapova's reign was short-lived, though, as Ana Ivanovic's French Open triumph moved her to the top, closely followed by her Serbian team-mate Jelena Jankovic. Over the past couple of weeks at Wimbledon several girls could have taken over from Ivanovic, especially with the early upsets of so many top seeds.

Jankovic, Sharapova and indeed Svetlana Kuznetsova are all in the mix for the No.1 spot when the new rankings are announced tomorrow, but it is highly likely that Ivanovic will hold on as she is there more by good luck than outstanding performances.

The closeness of the top five or even top 10 in the WTA rankings is great to see. It makes the tour a lot more competitive and fans look to see who can consistently play above the rest and take over from where Henin left off.

My answer to this question is simple: No one! I do not see any of the players being as dominant as Henin. They are all good on different surfaces, they all have various levels of experience and, with the increased depth in the WTA tour, domination is a thing of the past. I see a sea-saw battle commencing among the top eight women in the world for the rest of the year and probably most of next season.

Consistency is the key. Players simply need to play lots of tournaments, stay injury-free and do well at the Tier 1 and Grand Slam tournaments. Both Williams sisters, Venus and Serena, would have a chance but they simply don't play enough due to other commitments, injuries and short schedules.

Maybe having reached the Wimbledon final they may be more motivated now that Henin has gone. Jankovic, with a major victory, could go on to win many more but she needs that breakthrough very soon. Kuznetsova is a quality player but she lets her head go down when she goes through bad patches.

The most likely rivalry to develop is between Ivanovic and Sharapova. If Shara can sort out her shoulder then these two could be the players to beat. Whoever deals with the pressure best will triumph long-term. And look out for Elena Dementieva who is having a great season. She has lots of experience on tour and is playing well on all surfaces at the moment.

With a whole host of young talent coming through the ranks we are likely to see it getting even better. Competition for success is fierce and i think it is so difficult to predict who can become a long-term No.1. The ranking is likely to change hands many times over the coming years. Perhaps that might be a good thing.