In 1537, the Portuguese sent a fleet to attack Diu, which was defended by Zufar's land forces. Suleiman witnessed the preparations: In 1537, Sultan Bahadur and Khoja Zufar agreed to meet with the Portuguese governor
Nuno da Cunha in Diu, on his ship and despite being warned, Bahadur was murdered and his body thrown into the ocean, while Zufar barely escaped onto the ship of Antonio de Soto-Maior. Determined to avenge himself, Zufar wrote to his relative Nacoda Hamede, the ruler of Zebit, to send the Ottoman army to India, to which the Sultan approved. According to Portuguese author Luís Vaz Camões letters published in 1776, Zufar and Nunio had been serving together in service of the Portuguese, but Zufar, with a party of locals of Cambaya, switched side and joined Hadim Suleiman Pasha. In April 1538, Zufar, having received news of the Portuguese fleet preparing for war, secretly sent his wife and children to safety. He then presented himself before the new sultan,
Mahmud III, who made him governor of Surat with the title of Khudawand Khan. Zufar then made an attack on the outer fort of Diu, driving the Portuguese into the city, and initiating the
Siege of Diu which was made possible thanks to Zufar's close friend Ruy Freire, a Portuguese who collected information. In June 1538, Zufar was wounded by the Portuguese, and attacked again on June 26 with 4,000 men outside the village of Rome. Throughout his reign as a governor, Zufar had urged the Muslim leader of Gujarat to expel the Portuguese, who had taken possession of Surat Port and robbed the city at the beginning of the century. The following quote is attributed to him, as part of a speech to his men about the Portuguese: Delayed by other conflicts, Suleiman arrived with a fleet of 72 vessels, and told his men of a certain "Cosazaffer who originally came from Otranto and was a renegade for Islam". In 1540, to resist the attacks of the Portuguese, Zufar constructed a strong, high, and large fort in the place of the small old fort. The Portuguese protested against the decision. Zufar had a personal relationship with
Garcia de Orta as he would receive gifts of
curcas (cataputia minor), from Zufar. In 1542, a ship filled with 60,000 pieces of Venetian gold was sent to Zufar, to prepare for the incoming fleet. In 1545, Zufar attempted another siege of Diu and failed. In 1546, Zufar complained that his merchant vessels were harassed by the Portuguese
cartaz which resulted in skirmishes with the Portuguese fleets. The Sultan, determined to retake Diu, applied for support from Indo-Islamic states. In 1546, Zufar fortified his base at Surat and persuaded the sultan of Gujarat to once again attack Diu. In March, 1546, Zufar appeared in front of Diu with 7,000 "guzatteres" and 1,000 Turks in order to take it from the Portuguese. Their leader, Dom Joao Mascarenhas, defended the city as did his predecessor Antonio da Silveira. Portuguese women participated in the defence as well. The sieges failed and Suleiman departed on November 5. Zufar then set fire to his encampment and abandoned the island of Diu. According to Diogo do Cuoto, the keeper of the Portuguese Record Office in Goa, throughout the 1540s, Zufar received letters every year from his mother, a Catholic, who was much upset that Zufar had converted to Islam. == International writings ==