Simona Halep was troubled by injury in a loss to Dominika Cibulkova, while Caroline Garcia was beaten by Katerina Siniakova in Wuhan.
Simona Halep suffered a first-set bagel at the hands of Dominika Cibulkova as she made another early exit in Wuhan.
Zhang Zhizhen took Andy Murray to a deciding set before retiring injured from their first-round match at the Shenzhen Open.
Kateryna Kozlova caused a first-round upset at the Tashkent Open by knocking out top seed Irina-Camelia Begu in straight sets.
The Wuhan Open began with Kiki Bertens overcoming a hectic 24 hours and Garbine Muguruza earning a measure of revenge.
Nao Hibino improved her record against Eugenie Bouchard to 3-0 in 2018 with a 6-3 6-3 victory at the Tashkent Open on Monday.
Despite being a set and a break down to Bradley Klahn in Chengdu, Bernard Tomic recorded his first tour-level win since Wimbledon.
Serena Williams' coach admitted he tried to send her signals during the US Open final, yet she does not understand why he made that claim.
Team Europe made it back-to-back Laver Cup titles thanks to wins by Roger Federer and Alexander Zverev.
Anett Kontaveit fought back from a set down to stun ninth seed Sloane Stephens in the opening round of the Wuhan Open in China.
Serena Williams is "fighting for equality", according to LeBron James, who said he feels her "struggle".
The knee problem that forced Rafael Nadal to retire from the US Open semi-finals will keep him out of the China Open and Shanghai Masters.
Although the ATP felt Mohamed Lahyani's chat with Nick Kyrgios was "well-intended", it has suspended the umpire for two tournaments.
After surrendering her French Open title in the first round this year, Jelena Ostapenko won the opening match of her Korea Open defence.
French Open finalist Dominic Thiem has followed up making the last eight at the US Open by reaching the St Petersburg Open's quarter-finals.
Caroline Wozniacki had no answer to the brilliance of the unseeded Camila Giorgi in Toyko, ending her dreams of a third successive title.
Naomi Osaka's impressive homecoming moved up a gear as she moved into the semi-finals at the Tokyo Open.
Naomi Osaka proved a hugely popular winner after thrashing Dominika Cibulkova in Tokyo on Wednesday.