DUBAI, Feb 16: Serena Williams, the Australian Open champion, and Maria Sharapova, the world number one, have withdrawn from the Dubai Open starting on Monday, highlighting a growing crisis which has forced the WTA to speed up its reforms.

The sudden absence of the sport’s two most charismatic players is a shattering blow to the 1.5million-dollar tournament and an example of the kind of setback which threatens to damage the professional game.

Williams has cited flu and Sharapova a troublesome hamstring as the reason for withdrawing, a disappointment which has become so commonplace that the WTA recently released figures showing that withdrawals had reached record levels.

This prompted Billie Jean King, the tennis legend who was one of the founders of the WTA Tour, to comment: “We've got a challenge on our hands.”

Top ten player withdrawals from Tier 1 tournaments more than doubled from 2005 to 2006. Even more worryingly there has been an increase of 72 percent in top ten player withdrawals from the tour's top level tournaments over the past five years.

Arguably worse still, not one of the ten best tournaments in 2006 received the WTA Tour's commitment that a minimum of six out of the top 10 players will compete in every Tier I tournament — the first time this had happened.

The Dubai Open is now left with Justine Henin, making her first appearance of 2007 after what has been reported as marriage difficulties, as the top seed, with former world number one Martina Hingis and former US Open champion Svetlana Kuznetsova as her main rivals. —AFP