Jankovic lost in straight sets in Dubai on Wednesday
Third seed Jelena Jankovic tumbled out of the Dubai Championships with a 6-2 7-5 defeat by Estonia's Kaia Kanepi.
Ana Ivanovic, who has struggled for form, won 6-2 7-6 (7-5) against Camille Pin and the eighth seed will now play either Serena Williams or Jie Zheng.
Sixth seed Venus Williams swept to a 6-3 6-2 win and will next play fourth seed Elena Dementieva, who beat Anabel Medina Garrigues 6-1 6-3.
France's Virginie Razzano beat Daniela Hantuchova of 6-2 1-6 6-2.
The winner will face Russia's Elena Vesnina, who was leading 4-6 6-1 4-0 against Dominika Cibulkova when the 12th seed retired.
Eleventh seed Marion Bartoli also failed to finish her third-round match, pulling out when trailing fifth seed Vera Zvonareva 5-2.