WTA Finals qualifiers Maria Sharapova and Simona Halep recorded straight sets victories at the China Open on Tuesday (local time), but Singapore hopefuls Eugenie Bouchard and Agnieszka Radwanska were dumped out in second round upsets.
Bouchard, who lost in the final of last week's Wuhan Open, was beaten by unseeded German Sabine Lisicki 6-2 6-4, while Italian Roberta Vinci knocked out 2011 winner Radwanska 6-4 6-4.
The defeats left the Polish world number six and seventh ranked Bouchard waiting to book a qualifying spot at next month's WTA's season-ending championships in Singapore.
French Open champion Sharapova and Halep, runner up at Roland Garros, are already assured of places in the eight-woman field at the WTA Finals and they added further wins to their strong tallies in 2014 on Tuesday.
Russian Sharapova produced some bruising groundstrokes as she crushed Ukrainian Elina Svitolina 6-2 6-2, while Romanian Halep encountered some issues before overcoming Chinese wildcard Zhu Lin 7-5 6-4.
World number four Sharapova went for her shots throughout the contest on the Beijing hard courts, smashing some eye-catching winners but also coughing up five double faults among some wild errors.
She sealed victory when Svitolina could only hit a backhand long to put Sharapova through to a third round meeting with Spain's Carla Suarez Navarro.
"Happy with the way I've started the tournament. Hopefully I'll continue that in the next match," the Russian said.
World number 167 Zhu followed Sharapova's aggressive tactics as she led 5-4 in the first set against second ranked Halep, only to lose her composure and the match.
The Chinese produced 28 unforced errors as Halep's counter punching approach helped her claim a win that sets up a third round clash with 15th seed Andrea Petkovic, the German having little trouble in ousting American Madison Keys 6-2 6-3.
Former world number one Ana Ivanovic was another second round winner as she beat Swiss Romina Oprandi 6-4 6-2 on the Moon Court.
Serbian Ivanovic currently holds the eighth and final spot in the Race to Singapore standings.
Venus Williams was among other seeds making it through to the third round after the seven-times grand slam winner claimed a 6-4 6-3 victory over France's Caroline Garcia, while 13th ranked Czech Lucie Safarova beat German Mona Barthel 6-3 6-3.
Venus's sister Serena, the world number one and defending champion, faces Bulgaria's Tsvetana Pironkova later on Tuesday.