A quarter-final upset was on the cards when play stopped in Hong Kong, with Elina Svitolina facing defeat against Wang Qiang.
A resurgent Timea Bacsinszky overcame Aryna Sabalenka to set up a Tianjin Open semi-final against Karolina Pliskova.
Kevin Anderson was unable to gain revenge for his defeat in the Wimbledon final, losing to an inspired Novak Djokovic in straight sets.
A victory over Kyle Edmund at the Shanghai Masters means Alexander Zverev will be in London next month for the ATP Finals.
Kiki Bertens saw her hopes of picking up ranking points in Linz blocked by a resurgent Margarita Gasparyan on Thursday.
Nao Hibino bore the brunt of Singapore-seeking Elina Svitolina's anger in Hong Kong, the top seed sealing victory in less than an hour.
All the big names progressed to the last eight at the Shanghai Masters apart from Juan Martin del Potro, who withdrew due to injury.
Roberto Bautista Agut had never previously won a set against Roger Federer, but the Swiss was pushed all the way in a 6-3 2-6 6-4 win.
Marco Cecchinato pulled off a stunning defeat of Novak Djokovic at Roland Garros, but it was a very different story in Shanghai.
Roger Federer was left applauding a remarkable backhand volley on the stretch from Daniil Medvedev in his three-set win on Wednesday.
Youngsters Stefanos Tsitsipas and Denis Shapovalov won their respective matches at the Stockholm Open on Wednesday.
Rafael Nadal looks likely to feature in the revamped 2019 Davis Cup, but Gerard Pique is less sure over Roger Federer's involvement.
Novak Djokovic was at a low ebb after his French Open exit, but the Serbian has experienced an incredible upturn in fortunes.
Johanna Konta has had a 2018 to forget but the British number one reached round two in Moscow at Elise Mertens' expense.
Despite being knocked out of the Kremlin Cup on Wednesday, Karolina Pliskova's WTA Finals place was confirmed as Kiki Bertens also lost.