It commenced on 16 November, when the Austro-Hungarians under the command of Oskar Potiorek reached the Kolubara river during their third invasion of Serbia that year, having captured the strategic town of Valjevo and forced the Serbian army to undertake a series of retreats.

Petar Bojović, Stepa Stepanović, Pavle Jurišić Šturm and Miloš Božanović commanded the 1st, 2nd, 3rd and Užice Armies, respectively.

Few recruits had been gained from the newly acquired territories, and the Serbian army had been stretched by the need to garrison them against Albanian insurgents and the threat of a Bulgarian attack.

"[11] Under pressure from the Russians to launch their offensive and to keep as many Austro-Hungarian troops as possible away from the Eastern Front, the Serbs invaded Bosnia in September with the help of Chetnik irregulars until being repulsed after a month of fighting in what came to be known as the Battle of the Drina.

[5] The Armeeoberkommando (AOK) acknowledged that an undefeated Serbia severed Austria-Hungary's connection to the Ottoman Empire and prevented the completion of the Berlin–Baghdad railway.

The AOK also realized that the Austro-Hungarian Army's inability to defeat Serbia would discourage neutral countries such as Bulgaria, Romania and Greece, from joining the Central Powers and would tempt Italy to open up a third front against Austria-Hungary.

That strategy had worked in Putnik's favour during the summer months until heavy rainfall in September and early October had reduced Serbia's roads to "muddy quagmires," making the movement of troops, guns and wagons increasingly hard.

Ludwig Thallóczy, the section chief of the Austro-Hungarian Finance Ministry, wrote Potiorek in October to recommend "the West Europeanization of the Serbs with a strong hand" as soon as Serbia had been occupied.

Acknowledging the opportunity such conditions presented, Putnik told his closest advisors: "All my strategy consists in placing the 'Serbian national mud' between the enemy's fighting line and his supplies.

Putnik stressed that Serbia needed to hold the Kolubara and the towns within its vicinity and suggested that the Serbs make a separate peace with Austria-Hungary if that proved impossible.

[16] Putnik reasoned that Austro-Hungarian supply lines would become overstretched as their forces pressed deeper into Serbia, while the Serbs would continue to hold the railheads in the Serbian interior.

Morale plummeted amongst the Serbs, who were already significantly demoralized from a lack of cold-weather clothing and ammunition and were exhausted by the long retreat toward the Serbian interior.

[17] Valjevo's capture led the Austro-Hungarians to believe that they were on the verge of defeating Serbia and that its army was no longer a coherent fighting force.

Also, the geography of northwestern Serbia favoured defensive operations since the approaches to the Kolubara did not offer any cover for armies invading from the direction of Austria-Hungary, and the river itself was surrounded by mountainous terrain.

[25] The extensive series of fortifications and the difficulty of the terrain that they faced left the Austro-Hungarians with no choice but to conduct gruelling operations in the Serbian countryside, with almost no lines of communication.

During the assault, they made the mistake of attacking its better-defended right flank and were met with determined Serbian resistance, which prevented them from gaining any ground.

The military historian David Jordan notes that if the Austro-Hungarians had attacked the junction splitting the 1st and Užice armies, they might have cut the Serbs down the centre and gotten hold of an unimpeded passage to the Morava River.

[31] Thar led Potiorek to reinforce his positions around Lazarevac, which he aimed to capture and use as a pivot from which to attack Kragujevac while his right flank pushed down the West Morava valley.

As a result, combat on the outskirts of Lazarevac intensified once again, and the Serbian army managed to repulse every Austro-Hungarian assault despite a lack of ammunition.

The Serbs began to run out of shells, and Stepanović asked the Serbian Supreme Command for the artillery of the 2nd army to be redirected to its rear, as he felt that its failure to contribute to the defence of Lazarevac had frustrated his troops and hurt their morale.

[17] The Austro-Hungarians made further gains on 25 November and forced the Serbian Army from Čovka and Vrače Brdo with an intense artillery bombardment.

[32] Although the Serbian army had put up fierce resistance and inflicted heavy casualties on the Austro-Hungarians, Putnik became concerned that his lines were overextended.

[32] The Serbian people withdrew alongside their army, and many retreated to Niš, where news of Belgrade's fall was greeted "impassively" since it had been "expected since the beginning of the war."

[27] On 2 December, the anniversary of Franz Joseph's 66th year on the throne, Potiorek wrote that he was "laying town and fortress Belgrade at His Majesty's feet.

[32] Mišić exploited the brief respite by withdrawing the Serbian 1st army a full 19 kilometres (12 mi) from the front line[24] and ensuring that his soldiers had an opportunity to rest.

[34] On 2 December, he ordered his forces to attack the Austro-Hungarians all along the front, informing his officers that the offensive would be specifically to improve Serbian morale.

He wrote that in the last three to four days, the Serbian army had captured one Austro-Hungarian general, 49 officers and more than 20,000 troops, including 40 cannons and "huge quantities of war matériel.

[40] A directive issued by the Serbian Supreme Command on 16 December reported: "The recapture of Belgrade marks the successful end of a great and magnificent period in our operations.

"[38] Franz Conrad von Hötzendorf, the Austro-Hungarian Chief of the General Staff, attributed the defeat to a Serbian "thunderbolt from the south."

The battle achieved none of Austria-Hungary's objectives: it failed to knock Serbia out of the war, induce Bulgaria to join the Central Powers, and convince Romania to stay neutral.