Ai Sugiyama recovered from a slow start Saturday to defeat Thailand's Tamarine Tanasugarn as host Japan booked a ticket to the Fed Cup World Group playoffs in July.
Sugiyama, Japan's top player, dropped the first set at Ariake Tennis Park but came back for a 4-6, 6-3, 6-4 win over Tanasugarn.
In an earlier singles match, Japan's Shinobu Asagoe also lost the first set but rebounded for a 1-6, 6-0, 6-4 win over Suchanun Viratprasert.
Japan also posted a 6-1, 6-4 win in the doubles.