The Russian battled back from a set down to beat French Open champion Justine Henin-Hardenne in the final.
The victory earned the Belgian a place in the final of the German Open.
The duo meet in the semi-finals of the German Open.
Lindsay Davenport and Jennifer Capriati will clash for a place in the final of the Bausch and Lomb championships.
The defending champion was dumped out of the French Open in the second round by 86th ranked Italian Tathiana Garbin.
The Chinese number one beat France's 31st seed Emilie Loit and set up a clash with Italy's Tathiana Garbin, who stunned Justine Henin-Hardenne.
The world number one has been ordered to rest by doctors.
A medical report said the world number one is suffering from a viral infection.
The American reached the milestone after beating Amelie Mauresmo in the final of the Amelia Island tournament.
Amelie Mauresmo shocked the world number one 6-7, 7-5, 6-3 in the semi-finals of the Amelia Island championship.
The world number one beat Conchita Martinez 2-6, 7-5, 6-3 in the third round of the Amelia Island championship in Florida.
She beat fifth seed Justine Henin-Hardenne 6-3 6-3 in 74 minutes.
The world number one overcame Nathalie Dechy, while Jennifer Capriati beat Silvia Farina Elia at the Qatar Open.
The top seed overpowered Maria Sanchez Lorenzo 6-1, 6-0 in the Paris Open.
Belgian Justine Henin-Hardenne twice clawed herself back from the brink of defeat to beat Italy's Francesca Schiavone 4-6, 7-5, 7-5 in the final.
The top seed began her Australian Open quest with a pulverising 6-0, 6-0 win over 15-year-old Olivia Lukaszewicz on Monday.
But defending champion, Andre Agassi at 33 years is still the man to beat.
The Belgian thumped Yugoslav Jelena Dokic 6-0, 6-4 in the final of the Swisscom Challenge on Sunday
"Right now I am mentally and physically tired," said Clijsters after being beaten in the Swisscom Challenge semi-finals by Jelena Dokic.
The Belgian top seeds remained on course to meet in the final of the Swisscom Challenge.
The World number two stayed on a collision course with fellow Belgian and world number one Kim Clijsters.
The second seed was treated by medical staff after cramping during \n\nher semi-final win over Jennifer Capriati.
Simona Halep became the first Romanian in 40 years to lift the French Open trophy at Roland Garros on Saturday.
The duo require success at the U.S. Open not only to sate their own ambitions but to gain the upper hand in their personal rivalry.
The world No. 1 was beaten by unseeded Russian Lina Krasnoroutskaya in the third round of the Canadian Open.
The Belgian whipped Lindsay Davenport to reach the final of the Acura Classic. She meets Justine Henin-Hardenne.
The French Open champions says she is one of the players on the WTA Tour with enough self-belief to challenge Serena Williams.
Serena Williams has used her painful defeat at the French Open to spur her on at Wimbledon.\n\n
Belgian duo Kim Clijsters and Justine Henin-Hardenne once again fell victim to the raw power of Williams sisters Venus and Serena.