Japan capped their return to the Davis Cup's elite World Group by completing a 5-0 home whitewash of Ukraine on Sunday. World number five Kei Nishikori was rested for the two dead rubbers on the final day, as on day one, leaving Taro Daniel and Yoshihito Nishioka to put the finishing touches to a one-sided World Group playoff in Osaka.
Daniel beat Artem Smirnov 3-6, 7-5, 6-1 after rain had delayed the start of play and Nishioka thrashed Danylo Kalenichenko 6-2, 6-2.
Nishikori, who won Olympic bronze in Rio before reaching the semi-finals of the US Open earlier this month, heaped praise on his supporting cast.
"Our two young guys made a big jump in beating two tough guys," he said, referring to Friday's key victories over Sergiy Stakhovsky and Illya Marchenko, the world number 50.