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