(CNN) -- Venus Williams stayed on course for a semifinal showdown with her sister and world number one Serena with a straight sets win over fast-improving Alize Cornet of France in Dubai.
Venus powers a backhand during her straight sets win over Cornet in Dubai.
Wimbledon champion Venus proved too strong for 19-year-old Cornet as she reached the last eight with a 6-3 6-1 victory at the outdoor hardcourt event.
The sixth seed was never troubled after a close first set and now faces Russian fourth seed Elena Dementieva, who beat Spain's Anabel Medina Garrigues 6-1 6-3.
Australian Open champion Serena rounded off Wednesday's action with a 6-4 6-2 win over Zheng Jie of China in a night match.
But the lights went out for third-seeded Serb Jelena Jankovic who slumped to a shock 6-2 7-5 defeat by the 16th-seeded Estonian Kaia Kanepi.
Reigning French Open champion Ana Ivanovic also came through against French opponent Camille Pin, winning 6-2 7-6.
Earlier, former Wimbledon finalist Marion Bartoli was forced to quit with a foot problem while trailing 2-5 to Russia's Vera Zvonareva, the fifth seed.
Dominika Cibulkova of Slovavia fell unwell and had to retire when trailing 4-6 6-1 4-0 in the deciding set against Elena Vesnina.
Unseeded Russian Vesnina had put out seventh seeded compatriot Svetlana Kuznetsova in the previous round.