Zvonareva through as Kucova retires
Top seed Vera Zvonareva made it into the last eight of WTA Baku after Kristina Kucova retired during their second round match.
The Russian was already 6-0 3-0 up against an opponent who had struggled from the outset.
Zvonareva's opponent in the last eight will be Georgian Anna Tatishvil, who defeated compatriot Tatia Mikadze 7-6(4) 6-3.
Second seed Anastasia Pavlyuchenkova booked her place in the quarter-finals with a 6-4 6-0 win over fellow Russian Elena Bovina.
Pavlyuchenkova made a sluggish start to the clash, quickly finding herself a break down.
Bovina even held a break point for a 4-0 lead before the world number 13 found her rhythm and battled to the first set.
After taking the first set Pavlyuchenkova dropped just nine points as she scored a bagel second set to wrap up the win.
Kateryna Bondarenko also progressed to last eight when she upset fourth seed Ekaterina Makarova 6-1 6-4.
The Ukrainian, who has won only four main draw matches this year, was far too strong for her opponent and set up a clash with compatriot Mariya Koryttseva.