Cape Town - Top seeds Simona Halep, Angelique Kerber and Elina Svitolina booked their places in the last eight on the Qatar Open on Thursday.
Reigning French Open champion Halep took her head-to-head record against Lesia Tsurenko to 6-0 as she secured a comfortable 6-2, 6-3 victory in under 90 minutes.
Halep won the first five games of the opening set and, after a brief fightback from the Ukrainian, she also reeled off the final five games of the second set to advance.
Next up is Julia Goerges after the ninth-seeded German beat American lucky loser Alison Riske 6-1, 6-7 (5/7), 6-4.
Third seed Kerber had an easier day than compatriot Goerges as the three-time Grand Slam winner was a 6-1, 7-6 (7/2) winner over Anett Kontaveit from Estonia.
Fourth seed Svitolina secured her first-ever win over 2017 French Open champion Jelena Ostapenko as she won their encounter 6-4, 6-4.
Dutchwoman Kiki Bertens came through a three-set encounter as the fifth seed edged Carla Suarez Navarro from Spain 2-6, 6-1, 6-1 to secure a clash against Elise Mertens, who was a 6-2, 7-6 (7/3) winner over Kristyna Pliskova.
Pliskova only made the main draw after her sister second seed Karolina withdrew due to a viral illness.
Reigning French Open champion Halep took her head-to-head record against Lesia Tsurenko to 6-0 as she secured a comfortable 6-2, 6-3 victory in under 90 minutes.
Halep won the first five games of the opening set and, after a brief fightback from the Ukrainian, she also reeled off the final five games of the second set to advance.
Next up is Julia Goerges after the ninth-seeded German beat American lucky loser Alison Riske 6-1, 6-7 (5/7), 6-4.
Third seed Kerber had an easier day than compatriot Goerges as the three-time Grand Slam winner was a 6-1, 7-6 (7/2) winner over Anett Kontaveit from Estonia.
Fourth seed Svitolina secured her first-ever win over 2017 French Open champion Jelena Ostapenko as she won their encounter 6-4, 6-4.
Dutchwoman Kiki Bertens came through a three-set encounter as the fifth seed edged Carla Suarez Navarro from Spain 2-6, 6-1, 6-1 to secure a clash against Elise Mertens, who was a 6-2, 7-6 (7/3) winner over Kristyna Pliskova.
Pliskova only made the main draw after her sister second seed Karolina withdrew due to a viral illness.