Two Serbian armies were set up to defend the Despotate, the first commanded by Nikola Skobaljić in Dubočica, near Leskovac, and the second on the banks of the Sitnica River in Kosovo.

An initial invading Ottoman force heading from Sofia cut off Skobaljić's army from Serbia's north.

The young voivode disobeyed the despot, and the invading Ottoman army coming from Macedonia was met by Skobaljić near Banja.

Skobaljić continued his resistance against the Ottomans, operating in Southern Serbia and the Leskovac area, and scored another victory against the armies of the Sultan in the Battle of Kruševac with the help of John Hunyadi.

The failure of his generals to beat the small army of Skobaljić rendered Mehmed II to deal with the Serbian voivode personally.