Seeded trio Simona Halep, Karolina Pliskova and Carla Suarez Navarro booked last-16 spots at the Wuhan Open on Monday.
They became the first three players to make it through to that stage, having all been given first-round byes in China.
But aside from victorious seeds, the tournament continued to claim injury victims as there were four more retirements to add to a growing list.
SEEDS ENJOY SERENE PROGRESS
While Halep was the beneficiary of her opponent's retirement, fifth seed Pliskova overcame fellow Czech Lucie Safarova in straight sets to kick off her bid for a seventh WTA title in style.
Suarez Navarro was also convincing in a 6-4 6-3 triumph over Yanina Wickmayer.
And there were notable first-round wins for Caroline Wozniacki against Samantha Stosur, and 11th-seeded Briton Johanna Konta versus Annika Beck.
RETIREMENTS KEEP ON COMING
Belinda Bencic and Timea Bacsinszky were forced to withdraw on Sunday and the theme of retirements continued the following day.
The highest-profile casualty was 15th seed Anastasia Pavlyuchenkova, who was 3-1 down in the deciding set when she called it quits against Misaki Doi.
Anastasija Sevastova, Heather Watson and Irina-Camelia Begu suffered similar fates, the latter against fourth seed Halep.
STILL TO COME
Reigning champion Venus Williams begins her title defence on Tuesday against Yulia Putintseva, who was Sevastova's opponent.
Top seed Angelique Kerber now knows she will take on Kristina Mladenovic in her opening contest, while second seed Garbine Muguruza faces Jelena Jankovic.