How about that time that the Egyptian Mamluks, with secret support from Venice, battled the Portuguese in the sea off the coast of India?
When Vasco da Gama established a naval route between India and Europe in the late 15th century, the Portuguese were able to severely undercut the traditional path of the spice trade. The Portuguese actually claimed the entire Indian Ocean as their domain (the mare clausum is a topic for another time…). This brought them significant riches, but also made them a lot of enemies.
Two of those enemies were Venice and the Egyptian Mamluk Sultanate, at the time both key players in the overland spice trade. It was up to them to break Portugal’s stranglehold on the Indian Ocean. There was just one holdup: the Venetians had the sea power but not the political will, and the Mamluks had the will but not the sea power.
Venice did not want to get into open conflict with Portugal, so they sought indirect and secret diplomatic means to disrupt the Portuguese. One of the targets of their diplomacy was the Mamluk Sultanate of Egypt. The Mamluks were keen to do something but had almost no naval power, and almost no means to improve their naval power. Where, for example, would they get the wood for a fleet to rival the ascendant Portuguese?
Eventually a solution was reached. Timber was sourced from the Black Sea and sent to Suez – although as it was passing through Greece the Knights Hospitaller intercepted and seized fully half of the shipment. At Suez, the Mamluks secretly assembled a set of ships with the help of Venice. At last, in 1507, they were ready to attack.
They had other allies off the coast of India. Portugal was in the process of annexing territories all along the coast of India, and this too had made them many enemies. The Mamluk fleet was joined by galleys from the Gujarat Sultanate, and together they attacked Portuguese ships at the Battle of Chaul in early 1508.
The Portuguese lost – their ships were sunk, their commander Lourenço de Almeida (son of the viceroy of Portuguese India) was killed in action. It was the first defeat for Portugal in the Indian Ocean.
The Mamluk victory was short-lived: the Portuguese returned fire in a big way. The Battle of Diu nearly completely destroyed the Mamluk naval forces and sent the Mamluk Sultanate into a spiral from which they never recovered – they were conquered by the Ottoman Empire just seven years later.