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 Serbia (present-day North Macedonia).

The treaty included the full capitulation of the 11th Army, bringing the final tally of Bulgarian and German prisoners to 77,000 and granting the Allies 500 artillery pieces.

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.

Utilizing the cover of heavy artillery a Franco-Hellenic force made a rapid push into the enemy trenches, conquering Skra and the surrounding system of fortifications.

A total of 1,782 soldiers of the Central Powers became prisoners of war, including a small number of German engineers and artillery specialists that served in Bulgarian units; considerable amounts of military equipment also fell into Entente hands.

[12] In late July 1918, Bulgarian commander-in-chief Nikola Zhekov sent German Field Marshal 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.

[13] 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.

Widespread insubordination and desertions also plagued the Bulgarian troops who refused to participate in fortification works; poor rations and fatigue contributed to the low morale.

Bulgaria established combat security outposts at a distance of 2 kilometres (1.2 mi) from the enemy trenches, while also reinforcing the defenses of the dominant Dub and Kala Tepe mountains.

Similarly to Dobro Pole the defenses consisted of a series of mutually supporting trenches, with built in observation posts, machine gun positions and artillery pieces.

[16][17][18] 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.

On the same day, Scholtz sent Hindenburg a telegraph stating that [21] ... all indications point out that an enemy offensive will target the 11th Army on both sides of Vardar as well as Dobro Pole....[22]The Bulgarian high command did not attempt to perform a spoiling attack as they lacked the necessary vehicles and pack animals.

[23][24][25] 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 Shumadia 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 kilometres (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.

The 26th British Division seized a number of Bulgarian security outposts but was quickly repulsed by heavy artillery fire and counter-attacks that recaptured the lost ground.

In the aftermath of the engagement the Allied command found itself to be unable to make any further offensive operations on the Doiran sector as it no longer possessed an adequate reserve of manpower.

News of a breakthrough at Dobro Pole prompted the defenders of Doiran to abandon their positions and rush to the defense of their homeland, in order to prevent a future occupation by the Entente.

The Italians were ordered to strike Kičevo with the aim of preventing the enemy forces stationed at Monastir from reaching the railroad hub in Uskub, the 11th Colonial French Division was instead tasked with securing Prilep.

The Quadruple Alliance High Command set Uskub as the rallying point for its forces in Vardar Macedonia, intending to later strengthen them with units from Germany and Austria.

On the evening of 26 September, Italian cavalry wrestled Goloznica from a Saxon infantry unit, later entering Drenovo where it received information of a Bulgarian withdrawal from Veles.

Uskub was protected by a garrison of six and a half battalions, four armored trains and four artillery batteries split between a mountain range south of the city and a position north of lake Kaplan.

Between 27–28 September, the 1st and 4th French Colonial Regiments made their way through Drachevo and Pagaruza, successfully bypassing any sentries located in the 20-kilometre (12 mi) gap between the two Bulgarian formations that protected Uskub.

The assault was launched an hour later, French spahi utilized thick fog to advance on mount Vodna, however they were forced to regroup after facing heavy resistance.

[54][55] 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.