Operations were launched on the night of 17 December 1961. The Naval task was to gain control of the seaward approaches to the Bays of Marmagao and Aguada, prevent intrusion by Portuguese naval units, occupy Anjadip Island and provide fire support to the troops. INS Delhi was assigned to play the planetary role of Diu. On spotting two Portuguese vessels, she opened up with her guns and sank one of them, while her crew took hasty steps than other. Meanwhile naval ships had been patrolling off Marmagao and on the morning of 18 December they saw the Portuguese figate Afonso de Albuquerque in harbour. Her guns were firing at the Indian Air Force.
Indian naval ships Betwa, Beas and Cauvery closed in and engaged the frigate from a range of 8,000 yards. She was badly hit and huge fires broke out. Her crew quickly discarded her. As assault party from INS Venduruthy landed on shore to capture Anjadip, helped by heavy firing from INS Trishul. It managed to gain control over the southern part of the island, overcoming stiff resistance. A second party landed from INS Mysore to firm up communications. The capture of the northern part of the island proved more difficult; it was only after the 4.5" guns from Trishul intensively raked the equipped position that the battalion eventually surrendered.
