Maria set to regain world number one spot

Russia's Maria Sharapova is set to regain the women's world number one ranking after Amelie Mauresmo's surprise defeat in the Australian Open fourth round on Sunday.

After current top-spot holder Justine Henin-Hardenne withdrew from the Melbourne Park event for personal reasons, Sharapova ensured there would be a new No. 1 by reaching the last 16 at the year's first grand slam.

Sharapova and Mauresmo were set to vie for the elite ranking but with the French reigning champion's defeat in Melbourne and the Russian having fewer points to defend, most of the permutations were made redundant.

Only third seed Svetlana Kuznetsova can deprive her fellow Russian of top spot if she wins the tournament and U.S. Open champion Sharapova loses her fourth-round match to Vera Zvonareva on Monday.

Mauresmo has spent 39 weeks as the world number one in her career, while Sharapova, who last topped the rankings in August 2005, has enjoyed the honor for seven weeks.

Kim Clijsters, Martina Hingis and Serena Williams are the only other remaining women at the Melbourne Park event to have held the top ranking.