Naval Captain Enrique Simpson, commander of the blockading Chilean division, reported that on the night of July 7 an attack was attempted with a torpedo boat on the Matías Cousiño, a charcoal burner of the Chilean squad which was mistaken for the Abtao however in Peru, there were no documents or evidence that certified a torpedo attack.

The Huáscar arrived in Iquique at 0:45 am on July 10 and since there was no Chilean ship, 2nd Lieutenant Fermín Diez Canseco was sent to go ashore to get reports.

[3] The mission was over however, as there was no Chilean ship in the port, but Grau decided to set off again to look for them, despite the fact that the chances of running into the ironclad Almirante Cochrane, which he was forbidden to confront, were great.

The Matías Cousiño began to move so as to offer the smallest possible target, which didn't prevent at least three hits from affecting it, one of these projectiles penetrated her hull and lodged in one of her bunkers.

The Magallanes was under the command of the frigate captain Juan José Latorre and when he was 300 m away, he fired a can of shrapnel at him with his 64- pound cannon, starting the fight between the two, which was between 3:00 am and 3:35 am.

Due to this action, the Peruvian Congress recommended to the Executive to grant Miguel Grau the rank of Rear Admiral.