San Martín's column was the first one to reach the enemy. The two cannons and the cannon fire from the ships defended the royalists, but they were quickly outmanoeuvred by the sabre attacks and, unable to form a square, had to retreat. The advantage of surprise and the speed of the cavalry charge allowed the regiment to defeat the larger royalist army who had almost double their number of soldiers. When Bermúdez and his column joined the battle the royalists were not able to stand their ground and were routed, retreating in disarray under covering fire from the ships. Bermúdez led the attack at this point as San Martín had fallen from his horse.