Chinese Peng Shuai ended British hopes at the Birmingham WTA Open on Thursday with a 7-6(1), 6-1 win over teenager Heather Watson.
Second seed and former world number one Ana Ivanovic stepped up her quest for the title as she brushed aside Canada's world number 45 Rebecca Marino 6-3, 6-2 in 59 minutes.
Next up for Ivanovic is Mirjana Lucic, whose 6-2, 7-6(4) win over Andrea Hlavackova ensured her second quarterfinal appearance in two months, having previously failed to reach the last eight since 1999.
Fourth seed Daniela Hantuchova beat 16th seed Alla Kudryavtseva of Russia 6-4, 6-2, and will face American Alison Riske in the quarterfinals after Riske surprised French eighth seed Aravane Rezai 5-7, 7-6(6), 6-2.
In another upset, New Zealand's world number 151 Marina Erakovic beat seventh seed Sara Errani 5-7, 6-4, 6-3 to set up a quarterfinal showdown against Peng.