In this Saturday, Jan. 28, 2017 photo, United States' Serena Williams, left, embraces her sister, Venus, as she celebrates after winning the women's singles final at the Australian Open tennis championships in Melbourne, Australia. less In this Saturday, Jan. 28, 2017 photo, United States' Serena Williams, left, embraces her sister, Venus, as she celebrates after winning the women's singles final at the Australian Open tennis championships in ... more WHITE PLAINS, N.Y. - Serena Williams , Venus Williams and Angelique Kerber will sit out the first-round Fed Cup matches between the United States and Germany.