On 14 July 1898, Elliott was in command of Companies C and D, composed of 150 Marines and 50 Cubans, which were ordered to destroy the well at Cuzco, about from Guantanamo, and the only water supply of the Spaniards within . from Cuzco, half of the Cubans and the first platoon of Company C passed over a mountain to the left, hoping to cut off the Spanish pickets. In this they failed, and the main force was discovered by the Spanish outpost, which retreated immediately and gave the alarm to the main body, whose headquarters were in a house at Cuzco. A high mountain separated the two forces at this point and each attempted to gain its crest as a point of vantage. The Marines were successful, but were fired on heavily by the enemy from the valley. Following a straggling retreat by the Spaniards, the Marines began the return march, the well having been destroyed. For his eminent and conspicuous conduct in this engagement, Captain Elliott was advanced three numbers in his grade.