2016 US Open Champion Angelique Kerber def. 2018 Champion Naomi Osaka 6-4, 5-7, 6-4 in a hard fought match at the @WTAFinalsSG. What do you think was the defining moment of the match? _ 📸: Getty Images _ #USOpen #instatennis #tennis #AngeliqueKerber #NaomiOsaka #wtafinals #wta #singapore #wtatennis