Battle of Kolubara The Battle of Kolubara ( 3 – 9 December 1914 ) was a major victory for Serbia over the Austro - Hungaria n armies during World War I . The Austro - Hungarian armies were routed , and driven back across the Serbian border . Austrian advance . After the Battle of Drina , the Serbian army retreated to the right bank of the Kolubara River . The Serbian Army had 250 , 000 poorly equipped soldiers , the Austro - Hungarians had a well - equipped force of 450 , 000 men . On 16 November 1914 , the Austro - Hungarian Balkan Army group ( 5th and 6th Army ) , commanded by General Oskar Potiorek , launched an attack across the river . Potiorek ' s goal was to gain control over the railroad that led from Obrenovac to Valjevo and to use it for supplying his troops instead of using muddy roads in Mačva . The 5th Army , which held the northern part of the front , captured the town of Lazarevac which was held by the Serbian 2nd Army . In the south , the 15th and 16th Corps of the 6th Army attacked the 1st Serbian Army , captured Mount Maljen on 24 November , and put the Serbian left wing in a difficult situation . On 25 November , the Austro - Hungarian 5th Army pushed back the 2nd and 3rd Armies , crossed the Ljig River and out - flanked the 1st Army . Because the Serbian First Army was in a difficult situation , its general , Živojin Mišić , wanted to abandon his current positions and retreat to a new position in front of the town of Gornji Milanovac . His plan was to delay combat , rest his troops , and then launch a counteroffensive . Radomir Putnik , the Chief of the Serbian General Staff , did not approve of the plan . He warned Mišić that in that case other armies would also have to retreat , and Belgrade would have to be abandoned . Mišić told Putnik that the orders had already been given , and that he would not change them while he was in command . In the end , Putnik accepted the plan . When Belgrade was abandoned , Potiorek made a new plan . He wanted to amass the entire 5th Army in the Belgrade region to annihilate the Second Army , which was on the right wing of the Serbian front . The 5th Army would then turn to the south , get behind the Serbs , and force them to capitulate . Potiorek underestimated the offensive capabilities of Mišić ' s First Army in the south . He thought that they were too tired and weakened to do more than hold while his forces were maneuvering . The Austro - Hungarian soldiers were very tired even before this maneuver began . While they were marching , Serbian troops were resting in their new positions . On 2 December , Mišić finished all preparations for an attack . Putnik ordered the offensive to begin , using the entire Serbian army on 3 December . That was an ideal moment , because the largest Austro - Hungarian formation , the Combined Corps , was by then out of combat , marching north . Serbian counterattack . On 3 December , the First Army launched an attack against the surprised 16th Corps . The attack was supported by the Užice army from the left wing . 16th Corps suffered heavy casualties and was pushed back . On 4 December , 17th Corps tried to hold the advance of the 1st Army , but failed . Potiorek ordered an attack by the 5th Army so that he could complete his operation before the 6th army was defeated . However , the Combined Corps was still on its march . On 5 December , the First Serbian Army captured Mount Suvobor , the main defensive position of the 6th Austrian Army . Meanwhile , the Third Serbian Army had failed to push 15th Corps off Mount Rudnik , the Užice army suffered heavy casualties . However , these formations pressured the Austro - Hungarian forces and helped the First Serbian Army to achieve a breakthrough . In the evening , the Combined Corps arrived at its new position with very tired soldiers . On 6 December , Potiorek ordered the retreat of the 6th Army on the left bank of the Kolubara . Combined Corps finally attacked the Second Army , but the attack was easily stopped . The Combined Corps launched a major attack on 8 December , but the Second Serbian Army managed to hold its position . Other units of the 5th Army under General Liborius Ritter von Frank were more successful , but it was too late . The First Serbian Army had captured Valjevo and was pushing north . Vojvoda Putnik reinforced the Second Serbian Army with fresh troops and ordered an attack before the Austro - Hungarians could fortify their positions . On 12 December , Stepanović ' s 2nd Serbian Army attacked and defeated the 8th Corps . The 5th Army had to leave Belgrade and cross the Sava River on 15 December . The Serbian Army captured 76 , 000 enemy soldiers ; the number of Austro - Hungarian casualties was even greater . The invading army abandoned large quantities of military equipment , according to some sources enough " to equip three army corps " . Mišić was promoted to Vojvoda , while Potiorek was retired , replaced by Archduke Eugen of Austria who was placed both in command of the 5th army and as commander - in - chief of the Balkan army group from December 1914 . In 1914 the Austro - Hungarian Balkan Army Group lost around 224 , 500 men ( out of a total of 450 , 000 engaged in the battle ) , while the Serbian army lost around 170 , 000 men ( nearly its entire pre - war strength ) . Results . Austria had taken massive losses and yet failed to conquer or defeat Serbia . The Austro - Hungarian 5th and 6th Armies were driven out of Serbian territory , abandoning Belgrade to the Serbs . Meanwhile , it was under intense pressure from the Russian army on its eastern frontier . In a very unusual act , German emperor Wilhelm II personally congratulated Radomir Putnik on the victory . Since Serbia did not really pose a threat to Austria , the Austrians did nothing against Serbia for the next 10 months ; most of the forces in the area were transferred to the Italian front . On the other hand , although victorious , Serbian losses were even larger as a proportion of their army strength . Coupled with a typhus epidemic that raged through the countryside during the winter , Serbia remained on the defensive in 1915 , hoping for increased Allied support which never came .