Substitute Toshihide Matsui completed Japan's 5-0 whitewash against China in the Davis Cup tennis Asia/Oceania zone Group I first round tie on Sunday.
However, the 27-year-old from Chiba, who replaced veteran Goichi Motomura after Japan took an insurmountable 3-0 lead Saturday, had a tough battle against Sun Peng before winning 6-0, 4-6, 6-3 in the dead singles rubber.
Earlier Sunday, Davis Cup newcomer Go Soeda powered past Chinese ace Wang Yu 6-1, 6-1 to put Japan 4-0 up in the best-of-five contest.
"I used Soeda and Matsui in the important matches for the first time, but they did pretty well, never losing their concentration," said Japan's coach Eiji Takeuchi after stretching their record against China to 6-1.
"I'm going to choose different players for the next round. Our goal is to join the World Group. First of all, we are determined to beat Thailand," he added.
In the second round starting on April 7, Japan will take on Thailand, who also took an unbeatable 3-0 lead over Uzbekistan.