Azarenka and Serena set for rematch in Istanbul
Victoria Azarenka and Serena Williams will meet for the first time since the US Open final after they were drawn in the same group at the WTA Championships in Istanbul.
Williams, who triumphed in a thrilling three-set final at Flushing Meadows last month, will go head-to-head with the world No. 1 for a fifth time this season.
The American is in possession of two grand slam titles and an Olympic gold medal after a sparkling summer.
"I don't really care who I play or when I play, as long as I can play," Williams, who is bidding to win a third title at the season-ending event, said. "I'm really happy to be here. I'm on the red side with Victoria, so it'll be good."
"Every match here is tough. I obviously have great champions in the group. It's tough no matter what. It's challenging, definitely, but I'm looking forward to it," said Azarenka, who is also joined in the Red Group by Angelique Kerber and Li Na.
French Open champion and world No. 2 Maria Sharapova heads the White Group, which also features defending champion Petra Kvitova, Agnieszka Radwanska and Sara Errani.
The round-robin action gets underway on Tuesday, with the top two in each group progressing to the semi-finals.