She was part of a British fleet under Admiral Richard Howe successfully resupplied Gibraltar, then under siege by Bourbon forces. Shortly after, the British fleet met the Franco-Spanish fleet under Admiral Luis de Córdova y Córdova on 20 October 1782. The consequent battle of Cape Spartel was indecisive. "Polyphemus" was part of the second division of the van, and suffered four men wounded.