I felt better and better' - Last-minute alternate Bertens battles back to beat Barty at WTA Finals
WTA US Open: Naomi Osaka overcomes nerves. Bertens and Petkovic win
WTA Insider on Twitter: "What an effort from Kiki Bertens. Has played every week since US Open, arrived in Shenzhen @WTAFinals on Monday after playing the Zhuhai final, gets the call to
Osaka retires with injury, Bertens reaches WTA semifinals
Bertens books place in WTA Finals semis as Osaka pulls out due to injury - Social News XYZ
Bertens advances in Singapore after Osaka succumbs to injury | Euronews