Grigor Dimitrov(R)/Alexander Zverev react during the FAST4 of Sydney International match between Nick Kyrgios/Lleyton Hewitt of Australia and Grigor Dimitrov of Bulgaria/Alexander Zverev of Germany in Sydney, Australia, on Jan. 8, 2018. Nick Kyrgios/Lleyton Hewitt won 2-1.(Xinhua/Bai Xuefei)