Watch LIVE: Roger Federer takes on USA’s Jack Sock in the Hopman Cup (ESPN): livio acerbo on lacer2k and greengroundit Watch LIVE: Roger Federer takes on USA’s Jack Sock in the Hopman Cup (ESPN): livio acerbo on lacer2k and greengroundit Gennaio 4, 2018 January 04, 2018 at 10:20AM from ESPN via http://espn.go.com/