Seeded pair Ekaterina Makarova and Andrea Petkovic avoided first-round upsets at the Wuhan Open in China on Sunday.
The tournament's 13th and 16th seeds respectively, Makarova and Petkovic both moved safely into the second round of the inaugural WTA Premier hard-court event.
Makarova will now take on either Stefanie Voegele or Timea Bacsinszky after brushing aside Bojana Jovanovski 6-2 6-2 in just over an hour.
The world number 14 sent down eight aces in a relatively straightforward success while Petkovic was made to work harder in her 5-7 6-1 6-2 triumph.
After being broken three times in the opener, Petkovic found another gear to quickly turn the match on its head, ensuring a tie with Samantha Stosur or Korea Open champion Karolina Pliskova.
Ukraine's Elina Svitolina also booked a second-round berth as the world number 35 defeated Camila Giorgi of Italy 6-2 6-3.
France's Carolina Garcia came through 6-4 4-6 7-6 (8-6) against Venus Williams while Alison Riske was 6-4 4-6 6-6 (5-0) up against Shilin Xu before the Chinese retired, apparently struggling with the stifling heat.
Klara Koukalova came unstuck against Zarina Dyas, the Kazakh qualifier prevailing 6-4 6-7 (1-7) 6-2 while Italian Karin Knapp will face third seed Petra Kvitova in the second round after seeing off Marina Erakovic 6-4 2-6 6-1.
There was no such joy for Knapp's compatriot Francesca Schiavone, who was a set and a break up before losing to 2-6 7-6 (7-2) 6-4 against Kirsten Flipkens.
Russia's Svetlana Kuznetsova was a 6-3 6-2 winner over Kurumi Nara of Japan, and Barbora Zahlavova-Strycova was given a strong test by the experienced Daniela Hantuchova.
The Czech saved six of eight break points she faced to win through 7-6 (7-5) 7-6 (7-2) and could face another Slovakian in the next round - with Dominika Cibulkova or America's Madison Keys waiting.