[1][5] In what was "one of the bloodiest battles the Portuguese fought in south-east Asia", the Acehnese suffered so much damage they were forced to call off their plans to attack Malacca and returned to Aceh.

Iskandar Muda instructed Sultan Abdullah to prepare a large fleet to jointly attack Portuguese Malacca.

[1] As a result of this, in 1615, Iskandar Muda led a second successful campaign against Johor with a large fleet of 100 galleys, 150 ghurab, 250 junks, lancharas, calaluzes and 40,000 men.

[1] Come night, Diogo Mendonça Furtado sailed his light oar-vessels into the midst of the Acehnese fleet under cover of the darkness to scout it and conduct a surprise attack.

Due to their large numbers, Portuguese artillery caused great damage to the compact Acehnese fleet.

[1] By midday of the following day, the Acehnese returned to the mouth of the Formoso River and found the Portuguese galleons becalmed, therefore vulnerable, and separated into two groups due to a lack of wind.

Captain Dom João da Silveira ordered the lower gun-ports of his galleon closed, fearing that the Acehnese might climb into his ship through them, thereby preventing his heavy guns from being used.