Venus Williams is also drawn into the hard-hitting Red Group in Singapore
In a Twitter Q&A, Aussie No. 1 offers views on Mirka Federer, playing doubles with Andy Murray and more.
The Czech says he has suffered back pain since Wimbledon.
The Dutch-Swedish duo will make their first appearance at the WTA Finals.
The Oakland native is flying his San Rafael coop.
The Aussie had some highs and lows in 2017.
World No. 2 aims to win a seventh year-end title.
