 On September 15, a combined force of Serbian, French and Greek troops attacked the Bulgarian-held trenches in Dobro Pole ("Good Field"), at the time part of the Kingdom of Serbia (present day North Macedonia).The offensive and the preceding artillery preparation had devastating effects on Bulgarian morale, eventually leading to mass desertions.Despite being outnumbered and poorly equipped, certain Bulgarian units offered fierce resistance, delaying the Entente advance in Zborsko.