WTA roundup: Elise Mertens avoids day of upsets in Tunisia
Stan Wawrinka makes short work of Ivashka in Rome opener as Stephens advances
Olympic champion Zheng joins top seed Sabalenka in Beijing third round
WTA roundup: France's Clara Burel and Diane Parry fall in Tunisia
WTA roundup: Number five seed Zhu Lin falls in Nanchang opener to Diana Shnaider