Top seed Naomi Osaka won her first match at the Madrid Open on Sunday, beating Dominika Cibulkova of Slovakia.

The 21-year-old Japanese overpowered 2016 Madrid Open finalist Cibulkova in the two hour tug-of-war, hitting eight aces on the red clay court. After a favorable first set, Osaka fought hard in the second set coming from behind, and eventually defeated the world No 33 Slovak 6-2, 7-6 (6).

In the second round, Osaka will face Sara Sorribes Tormo, who eliminated her Spanish compatriot Lara Arruabarrena 6-4, 3-6, 6-1 on Sunday.

Zheng Saisai became the sole Chinese player, out of four, having survived the first round as the 25-year-old beat compatriot Wang Yafan 7-5, 7-6 (3) to advance.

No 15 seed Wang Qiang was ousted by Croatian Donna Vekic 7-5, 6-4. In their last match at the 2017 Miami Open, Wang Qiang fought back from a set down to fend off Vekic 0-6, 6-4, 6-2.

Another Chinese, Zhang Shuai, was beaten by Kateryna Kozlova of Ukraine 6-3, 6-2.