Petra Kvitova lost in the Wimbledon first round for the first time since 2009 as she suffered a remarkable loss to Aliaksandra Sasnovich.
Svitolina, Rybarikova and Sevastova all suffered shock losses in the first round, while Pliskova, Radwanska and Venus Williams survived.
Sloane Stephens exited Wimbledon 2018 at the first hurdle as she lost in straight sets to World No.55 Donna Vekic.