Injury has forced world number two women's tennis player Maria Sharapova of Russia to withdraw from the JP Morgan Chase hard court tournament in California, delaying her move into the world number one spot.

Sharapova - the top seed - pulled out of Friday's quarterfinal match with Slovakian ninth seed Daniela Hantuchova due to a chest muscle injury.

Had she advanced to the semifinals, Sharapova would have taken over the world number one ranking on Monday from current top player Lindsay Davenport of the United States, who also is injured.

However, the 18-year-old Russian phenom will still automatically ascend to the world number one position on August 22, due to Davenport's injured status.

Sharapova's withdrawal Friday allowed Hantuchova to automatically advance to the round of four. She next takes on third seed Elena Dementieva of Russia, who defeated Tathiana Garbin of Italy, 6-1, 6-1.

Fifth seed and former world number one Kim Clijsters of Belgium beat fourth seed Nadia Petrova of Russia, 6-4, 6-2 to advance to the semifinals where she will play Italy's Francesca Schiavone.

The 13th seeded Schiavone reached the round of four with a 7-5, 6-4 win over Conchita Martinez of Spain.

Some information for this report provided by AP, AFP and Reuters.