Elina Svitolina and Venus Williams led the first-round winners at the Hong Kong Open.
Top seed Svitolina lost the first three games against Zarina Diyas but recovered to post a 6-4 7-6 (7/2) victory.
Williams, the second seed, was playing her first match since losing to Sloane Stephens in the semi-finals of the US Open and eased to a 6-2 6-2 victory over Risa Ozaki.
Defending champion Caroline Wozniacki was in blistering form against Eugenie Bouchard, racing to a 6-1 6-1 win in less than an hour, while fourth seed Agnieszka Radwanska beat Zhang Ling 6-1 6-2.
Fifth seed Elena Vesnina was the major casualty, the Russian losing 6-3 6-4 to Luksika Kumkhum.
All singles matches at the Tianjin Open were cancelled for the second straight day because of rain.
British number three Naomi Broady lost in the opening round of the Upper Austria Ladies Linz Open as she was beaten in three sets by Bulgarian qualifier Viktoriya Tomova.
The 27-year-old was unable to take advantage of her lucky loser spot as she was defeated 3-6 7-6 (8/6) 6-4 in two hours and 10 minutes.