Russia's Maria Sharapova swept aside Danish teenager Caroline Wozniacki 6-0, 6-1 on Friday to reach the Qatar Open semi-finals and set up a revenge clash with Polish teenager Agnieszka Radwanska.
But third-seeded Serb Jelena Jankovic joined the long list of upset victims at the tournament when she lost 6-3, 6-4 to unseeded Li Na of China.
Fourth-seeded Sharapova surrendered only eight points in the first set and took command in the second when her opponent netted a backhand volley to give her a 2-1 lead.
The Australian Open champion was only even remotely under pressure when she had to fight off four break points before holding for 5-1.
"Apart from that one game in the second set I felt pretty comfortable out there," Sharapova told reporters after her one-hour victory. "From the beginning of the match I was aggressive, I served and returned well and felt pretty good."
Now she has a potentially difficult meeting with 16th seeded Radwanska, who beat Dominika Cibulkova 6-4, 6-7, 6-4 after the Slovak upset sixth seed Venus Williams in the previous round.
Radwanska produced one of the biggest upsets at last year's US Open when she beat Sharapova in the third round.
"I never like losing to an opponent twice in a row so I'm quite excited about the challenge," said the Russian. "I was hoping she would win today so I could get an opportunity to go out and play against her again.
"But she's also very young and this is a new opportunity for her to be in the final of a big tournament, so I have to go out there and try to be aggressive as I was today and hopefully come out with a win this time."
Jankovic found little rhythm or consistency against an aggressive Li Na, who since returning in January from a six-month injury break has won the Gold Coast event in Australia and reached the semi-finals in Antwerp.
Sybille Bammer claimed her first career win over a top 10 opponent on Thursday when she beat second-seeded Russian Svetlana Kuznetsova but the 15th seed failed to build on her success, losing 2-6, 6-2, 6-0 to Russia's Vera Zvonareva.
