前江省
The Tây Sơn reinforcements led by Nguyễn Huệ reached Gia Định in 1785. Huệ sent an envoy to Siamese army under a banner of truce. Huệ showed fear deliberately, requested Siamese not to support Nguyễn Ánh. It proved that it was an excellent stratagem; Thepharirak was taken in. On the morning of 20 January 1785, Siamese fleet was surrounded in Rạch Gầm River and Xoài Mút River (near Mỹ Tho River, in present-day Tiền Giang Province). The battle ended with a near annihilation of the Siamese fleet, all the ships of the Siamese navy were destroyed. Thepharirak and Nguyễn Ánh fled back to Bangkok.