On 21 November 1856, two days before the engagement, Walker ordered the destruction of Granada, his capital, to keep the city out of enemy hands, and fell back and fortified himself at Rivas.

His situation deteriorating, he planned to escape, if need be, by fighting his way out of Rivas to the port of San Juan del Sur, where he could rendezvous with his navy––the schooner Granada––and return to California.

The Costa Rican brig Once de Abril was named in honor of their victory over the filibusters at the Second Battle of Rivas, sevens months earlier.

The engagement continued for two hours, the ships closing to within one hundred yards of one another, until, at around 8pm, a shot from Granada hit the magazine aboard Once de Abril, causing part of the brig to blow up and set afire.

[3][4] The engagement was one of the few clear victories of Walker's enterprise in Nicaragua, but by this point in the war had no effect on improving his dire strategic situation.