Iga Swiatek rows with opponent after thundering serve against her body

World No. 1 Iga Swiatek and Zheng Qinwen exchanged words over the net while warming up before their match in the United Cup quarterfinals as Poland played China. Iga Swiatek infuriated Zheng Qinwen minutes before their quarterfinal singles match at the United Cup after the World No. 1 hit her Chinese opponent with a serve…