Ayumi Morita beat Slovenia's Polona Hercog 3-6, 7-6 (6), 6-1 on Sunday as Japan advanced to the Fed Cup World Group playoffs.
Morita recovered from a sluggish start in the first set to give Japan an insurmountable 3-0 lead after Sunday's first reverse singles match.
Hercog experienced pain in her neck during the second set tiebreak and won only six points in the next five games as Morita streaked to a 5-0 lead in the final set.
"Against a player like Morita, I don't think I have a chance unless I am 100 percent," Hercog said. "My serve wasn't 100 percent and I couldn't move 100 percent."
Morita and Kimiko Date-Krumm combined to give Japan a 2-0 lead in the World Group II tie with singles wins on Saturday. With the win, Japan advanced to a playoff against the losers of the World Group.