was the start of eight games in a row without reply . Williams retains WTA Finals title . Beats Simona Halep 6-3 6-0 in title match in Singapore . Halep thrashed Serena Williams in round robin match 1992 . eighth victory in season-ending championships for Williams .
Williams retains WTA Finals title . Beats Simona Halep 6-3 6-0 in title match in Singapore . Halep thrashed Serena Williams in round robin match 1992 . eighth victory in season-ending championships for Williams .