In the early 18th century, the Maratha Empire was in a phase of aggressive expansion, seeking to consolidate its power in western India. The Portuguese, having established their presence in India since the late 15th century, controlled several coastal regions, including the vital fort of Vasai. On February 17, 1739, a large Maratha force, under the command of various generals loyal to Chhatrapati Shahu Maharaj, began its move toward Vasai to challenge Portuguese authority. Historical intelligence indicated the Portugeuse were vulnerable, prompting the Marathas to exploit this opportunity for conquest. Preparations had been meticulous, with strategic planning and intelligence-gathering bolstering their advance.

As the Marathas approached, they were welcomed by local populations, who were often disenchanted with Portuguese rule. This discontent among the locals facilitated the Maratha incursion, gathering support as they progressed. These dynamics of local collaboration significantly impacted the outcome of the battle, which would come to define colonial control in the region. The fighting was characterized by both traditional combat and guerrilla tactics, highlighting the tactical adaptiveness of the Marathas. The siege of Vasai would continue for multiple months, ultimately leading to its capture and the deterioration of Portuguese power in India.