Olympic champion Zheng sharp in swift third-round US Open win over Niemeier
WTA roundup: Jule Niemeier stuns Maria Sakkari in Bad Homburg
Lucky loser Niemeier knocks out top seed Sakkari at Bad Homburg
WTA roundup: Liudmila Samsonova continues DC title defence with Sorana Cirstea victory
WTA roundup: Jennifer Brady returns with win in Washington
Iga Swiatek quells Jule Niemeier challenge in testing opener
Swiatek survives surprise test from Niemeier to reach US Open quarters
