Jacob Fearnley defeated the former world number four Kei Nishikori 6-3 6-3 on a debut in the Davis Cup to equal the first round of the UK tie Britain with Japan.
The 23-year-old, who defeated Nick Kyrgios at the Australian Open earlier this month, has increased to 77 world rankings out of 646 over the past 12 months.
The British number three continued its rise against Nishikori to equalize the qualifier for 1-1, after the victory of Yoshihito Nishioka 7-5 6-1 against Billy Harris in Miki.
The tie will be decided on Saturday, when Fearnley takes over Nishioka and Nishikori faces Harris, otherwise Friday singles.
British duo Neal Skupski and Joe Salisbury play in the doubles Yosuke Watanuki and Takera Yuzuki.
British number one Jack Draper pulled out of the tie to continue rehabilitation from the hip injury.
Cameron Norrie, British number two, withdrew with the disease and its replacement Jan Koinski.
