The sisters will be at the same International-level event for the first time since 1998.
Madison Keys knows the pain pony tails pose; Ana Ivanovic has an answer.
Nick Kyrgios, Jack Sock and Garbine Muguruza will also join the field.
The Slovakian wanted to forget more than the ball girl by the end of her straight-sets loss to Madison Keys.
Former partners reunite for WTA Finals opener vs. Chan sisters.
Madison Keys electrified the crowd in Singapore with this magical forehand pass on Tuesday.
"I know what to do to go for it and just take the game in my hands," says world No. 1.
