Fifth-seeded Kim Clijsters [Images] continued her fine summer hard court play, knocking out Russian Nadia Petrova [Images] 6-4, 6-2 to reach the semi-finals of the Los Angeles Open tennis tournament on Friday.

Slovakian Daniela Hantuchova [Images] advanced with a walkover against top seed Maria Sharapova [Images], who withdrew from the event with a chest injury.

Sharapova's pull-out prevented her from gaining the number one ranking this week, but she will obtain the top spot nonetheless on August 22 because current number one Lindsay Davenport [Images] is injured.

Hantuchova will play number Elena Dementieva [Images] of Russia [Images], who crushed Italian qualifier Tathiana Garbin 6-1, 6-1.

Clijsters will meet number 13 Francesca Schiavone of Italy [Images], who took down 33-year-old Spaniard Conchita Martinez 7-5, 6-4.

Clijsters moved the tall Petrova all over the court by mixing up her angles.

She has lost only one match this year on US hard courts en route to winning three titles.

"The Russians play a similar type of game, they hit the ball hard and consistent. I enjoy playing them," Clijsters said. "I kept her moving from side to side. I had to mix it up."

Dementieva ran straight past the overmatched Garbin, who was blinded by the two-time Grand Slam finalist's speed.

"It's been a long time I could finish the match like that in less than an hour," Dementieva said. "I was feeling very confident with every shot that I was making. I played too fast for her. Everything I tried worked, even my drop shots."

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