Paraguayan general Bernardino Caballero's troops launched guerrilla-style raids on the Allied encampment in the Tayí area, near the Humaitá Fortress.

[1] On October 3, 1867, Bernardino Caballero left Humaitá with some 800 riders heading for San Solano, to launch himself by surprise over Brazilian forces, weakening the right flank of the allies.

In the vicinity of Tayí Island, there was an advanced Paraguayan group protected by a detachment led by captains José González and Pascual Urdapilleta.

Bernardino Caballero's cavalry, along with his officers Valois Rivarola and Antonio Olavarrieta, arrived at the rescue of the Paraguayan detachment, crushing the attackers.

Caballero, seeing the Brazilian soldiers, about three cavalry regiments and two infantry, approaching his position dangerously, ordered Major Viveros to remain in the detachment, while he went with his riders to meet the enemies.