Kammala wannan jumla: Sugita da Naomi Osaka sun wakilci Japan a cikin jinsi
Kofin Hopman na shekara ta 2018. Ya rasa wasan sa na wasa guda zuwa Roger Federer 6<unk>4, 6<unk>3, amma tsalle-tsalle a samansa ya faranta wa magoya baya rai kuma an haɗa shi a cikin yawancin shirye-shiryen bidiyo na farkon farkon kakar 2018. A gasar Australian Open ta 2018, Sugita ya sami nasararsa ta farko a kan dan wasa na Top 10 ta hanyar kayar da lambar duniya ta 9 Jack Sock a cikin saiti huɗu. Ya rasa a zagaye na gaba zuwa Ivo Karlović. A watan Fabrairun ya yi rashin nasara a zagaye na farko a Rotterdam zuwa Grigor Dimitrov. A watan Maris Horacio Zeballos ya doke shi a zagaye na farko a Indian Wells, kuma Robin Haase a zagaye na farko a Miami. A watan Afrilu ya rasa a zagaye na farko zuwa Jan-Lennard Struff a Monte-Carlo, Guillermo Garcia-Lopez a Barcelona, da kuma Yannick Maden a Munich. A watan Mayu ya yi rashin nasara a zagaye na farko da Philipp Kohlschreiber a Madrid da Ryan Harrison a Rome. A watan Yuni Sugita ya yi rashin nasara a zagaye na farko na gasar Faransa ta bude wa Horacio Zeballos. Daga baya a cikin watan ya rasa a zagaye na biyu a s-Hertogenbosch zuwa Marius Copil; kuma mako mai zuwa a Halle ya doke duniya # 7 Dominic Thiem a madaidaiciyar saiti, a cikin abin da ya ce shi ne "mafi kyawun wasa a rayuwata", kafin ya rasa a wasan kusa da na karshe zuwa Denis Kudla. A Antalya, Turkiyya, Sugita ya rasa a zagaye na biyu zuwa Pierre-Hugues Herbert. A watan Yuli ya yi rashin nasara a Wimbledon zuwa Bradley Klahn a zagaye na farko. A watan Agusta ya rasa a zagaye na farko zuwa Vincent Millot a Washington; ya rasa a zagaye na farko zuwa Ilya Ivashka a Toronto; ya rasa a zagaye na farko na cancantar a Cincinnati; ya rasa a zagaye na farko zuwa Leonardo Mayer a Winston-Salem; kuma ya rasa a zagaye na farko na US Open zuwa Richard Gasquet. Sugita ya fara mako bayan US Open tare da rikodin nasara 8 da asarar 22 a shekara, kuma matsayinsa na # 98 a duniya. A watan Oktoba ya sami katin daji a cikin Tokyo Open, kuma ya rasa a zagaye na farko ga ɗan ƙasar Kei Nishikori.