Agnieszka Radwanska has added 18 time Grand Slam champion Martina Navratilova to her coach staff.
It proved a happy Halloween for Czech Petra Kvitova after she made the most of coming back from the dead to set up a title-match showdown with Agnieszka Radwanksa at the WTA Finals.
Top seed Andy Murray could meet Roger Federer or Kei Nishikori in the third round, while Serena faces tricky Belinda Bencic in opening round
Maria Sharapova recovered from a second-set meltdown to record her first victory at this year's WTA Finals with a 7-5, 6-7(4), 6-2 triumph over Poland's Agnieszka Radwanksa on Friday but the Russian still bowed out of the elite eight-woman tournament.
Top seed Serena Williams shook off a spirited attempt by Agnieszka Radwanska and moved into the final of the Rogers Cup with a 7-6(3), 6-4 victory on Saturday and will meet Romania's Sorana Cirstea, whose surprising run continued when she beat China's Li Na 6-1, 7-6(5).
Second seed Garbine Muguruza, bidding to add the Wimbledon crown to her French Open title, was sensationally beaten in the second round on Thursday by Slovakian qualifier Jana Cepelova 6-3, 6-2 in the shock of the tournament so far.
Swiss qualifier Timea Bacsinszky continued to swipe past the seeds at the Wuhan Open on Wednesday by dumping World No 4 Maria Sharapova from the hard court tournament with a 7-6(3), 7-5 victory.