On 15 September, 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 Greece and North Macedonia).

The Central Powers' defeat at the Dobro Pole played a role in the Bulgarian withdrawal from the war and opened the way for the subsequent capture of Vardar Macedonia.

The conflict quickly attracted the involvement of all major European countries, pitting the Central Powers against the Entente coalition, and starting World War I.

In June 1917, the Venizelists gained full control of the country, immediately declaring war on the Central Powers and joining the Allied Army of the Orient operating on the Balkan Front.

[7][8][9] In late July 1918, Bulgarian commander-in-chief Nikola Zhekov sent German field marshal general Paul von Hindenburg a message regarding a rumored Entente offensive, and detailed Bulgaria's inability to adequately defend the Vardar portion of the front.

Hindenburg's reluctance to support Bulgaria was also manifested by the early September redeployment of the last German Jäger battalion stationed in Macedonia back into Germany.

[10] The Bulgarians, using information from escaped prisoners of war, determined that Entente forces would engage in hostile actions west of lake Ohrid, in Monastir, Dobro Pole or Human.

Von Scholtz had, however, failed to take into account the departure of Bulgarian chief of staff Nikola Zhekov and his subsequent replacement by Georgi Todorov.

Dobro Pole was surrounded by a well-developed system of trenches which, in combination with the rough terrain, made the area impassable for wheeled transport.

[14][15] D'Espèrey expected to march the Allied Army of the Orient through the towns of Demir Hisar, Rupel, Petrici, Blagusa, Gradec, Štip and Belessa, finally seizing Skopje.

Units stationed at Katsania and Tetovo would prevent a Bulgarian flanking maneuver, while the main body of the force would widen the breach both in Štip and Prilep.

In case of a collapse of the front between Dobro Pole and Tzena, the 1st Bulgarian and 11th German armies would either be annihilated or, in less favorable circumstances, perform an organised retreat to a new defensive line on the river Crna.

On the same day, Scholtz sent Hindenburg a telegraph stating that "all indications point out that an enemy offensive will target the 11th Army on both sides of Vardar as well as Dobro Pole ..." The Bulgarian high command did not attempt to perform a spoiling attack as they lacked the necessary vehicles and pack animals.

On the night between 14 and 15 September, Franco-Serbian patrols reported that the artillery barrage had dealt sufficient damage to the barbed wire entanglements separating the trenches.

[19] Two Franco-Greek regiments attempted to storm Zborsko but were pushed back in the ensuing counterattack, as powerful pockets of resistance between the Sousnitsa and Bigrut streams facilitated its defense.

Using dispersed bluffs as cover, soldiers of the Šumadija Division took over Veternik, Kamene and the western part of a nearby mountain range with considerable difficulty.

By the end of the day, Bulgaria lost approximately 40–50 percent of the 12,000 soldiers involved in the battle, including 3,000 prisoners of war, 2,689 dead and 50 out of the initial 158 artillery pieces.

By the end of the day, Allied troops had advanced 15 km (9.3 mi) into enemy territory while also seizing locales of strategic importance that would later enable them to continue pushing deeper into Vardar Macedonia.

[27][28][33] On 29 September 1918, the German Supreme Army Command informed Kaiser Wilhelm II and the Imperial Chancellor Count Georg von Hertling, that the military situation facing Germany was hopeless.

In Serbia, "Desperate Frankie" (as the British nicknamed d'Esperey) continued to advance and the Serbo-French Army re-captured the country, overrunning several weak German divisions that tried to block its push near Niš.