Wimbledon champion Maria Sharapova swept into the semi-finals of the China Open in Beijing on Friday when opponent Jelena Jankovic retired hurt in the first set with an ankle injury.

The 17-year-old Russian third seed will meet compatriot Svetlana Kuznetsova after the U.S. Open champion beat Argentine Gisela Dulko 6-4, 6-2.

Sharapova was cruising 5-2 when Jankovic of Serbia and Montenegro took a medical time out and threw in the towel down 40-15 in the eighth game.

Jankovic, seeded seventh, said she had twisted her right ankle during her second-round win over Japan's Shinobu Asagoe on Wednesday.

"I'm really disappointed... I was hurting and couldn't play balls left and right, I couldn't really move," the former junior world number one told reporters.

"Maria did what she had to do, she moved me around."

Sharapova was lethally accurate from the baseline, pinpointing groundstrokes that Jankovic could not chase down.

"I was happy to play a very good set. Though she was injured, we did have some good points," Sharapova said, calling Jankovic's injury very unfortunate.

"For me, it's an advantage that the second round was easy. I liked the way I was playing and today too ... I'm still enjoying myself, that's the most important thing," Sharapova added.

Looking forward to the Saturday semi-final, Kuznetsova said: "It's going to be a difficult match. Maria is playing well and so am I... It will depend on what game she plays and what I do."

The second seed produced a performance full of baseline power, strong serving and soft touch as she posted her 13th consecutive victory in just over one hour.

Down three break points at 4-4 in the first set, Kuznetsova slammed three superb winners to get herself out of trouble. The 19-year-old world number five then broke Dulko's serve to take the set.

Dulko, the sixth seed, wilted in the second set under Kuznetsova's relentless pace and meekly ended the match with a double fault.

"I'm in good shape. I've been tired here, but I think I can handle it," said Kuznetsova, who followed up her first Grand Slam title with victory in Bali last week.