Belinda Bencic stood firm to reach the quarter-finals of the Abu Dhabi Open while fellow favourites Anett Kontaveit and Jelena Ostapenko headed home.

Bencic clinched her second last-eight spot of the year with a 6-4 7-5 win over Marta Kostyuk, though the world number nine was pushed hard by the Ukrainian, who remains without a top-10 win in her career after failing to see through the second set from 5-3 up.

The second seed will next face Shelby Rogers, who advanced courtesy of a walkover following Kontaveit's retirement through injury after falling 4-1 behind in the pair's decisive third set. 

Kontaveit was not the only seed to fall, with Ostapenko slipping to a surprise 7-6 (12-10) 6-1 loss against China's Zheng Qinwen.

Fourth seed Veronika Kudermetova fared better, however, racing to a 6-1 7-5 win against Elise Mertens to keep her campaign alive. 

At the Linz Open, top seed Maria Sakkari cruised to a straight-sets success against Varvara Gracheva, while Anastasia Potapova battled to a 7-5 3-6 6-3 victory against Jule Niemeier.

Third seed Irina-Camelia Begu was the highest-ranked player to exit in the last 16 in Austria, suffering a 6-2 6-1 defeat against Danish 20-year-old Clara Tauson.