Morigami dominated the first set at the $600,000 WTA Tour event. In the second set, Bammer broke Morigami's serve in the eighth game to lead 5-3 and then served out the set.
The 20th-ranked Austrian broke Morigami in the third game of the decider before dropping her own serve in the sixth and eighth games.
Morigami's series of unforced errors helped Bammer recover and she won after her opponent sent a backhand out.
"Akiko is a good player and she gave me a tough contest," Bammer said.
Defending champion Yaraslova Shvedova of Russia was knocked out by
Akgul Amanmuradova. The big-serving Uzbek won 6-3, 3-6, 6-3.
Shvedova won her first WTA Tour title at Bangalore last year against defending champion Mara Santangelo of Italy. The Russian was unseeded this year as the tournament attracted a stronger field after being upgraded.
Fifth-seeded Agnes Szavay of Hungary defeated Indian wild card Shikha Uberoi 6-1, 6-4 and Aiko Nakamura of Japan rallied from a set down to beat Tamarine Tanasugarn of Thailand 6-7 (5), 6-1, 6-2.