The Serbs retook Rašulijača at noon, and the 1st Combined Division exploited this to advance towards Lešnica. Meanwhile, the 1st Morava Division attacked Iverak and managed to drive the Austro-Hungarians back. The village of Velika Glava fell to the Serbs before mid-day, and by the late afternoon the Rajin Grob ridge had been retaken. At around this time, the Austro-Hungarians began retreating with increasing rapidity, their will and cohesion apparently shattered. The 3rd Army had similar success, routing the 36th Infantry Division and forcing it to retreat in considerable disorder. The Serbs then moved to pursue the fleeing Austro-Hungarians all along the front. By 20 August, Austro-Hungarian forces were fleeing across the Drina River, still being pursued by the Serbs back into Bosnia, with the entire 5th Army being forced across the Austro-Hungarian side of the river. Many Austro-Hungarian soldiers drowned in the water as they fled in panic. Serbian military reports announced that the enemy is withdrawing in the greatest disorder. Putnik then notified King Peter in a telegram, saying the main enemy has been defeated in Jadar and on Mount Cer, and our troops are in hot pursuit. Upon their triumph at Cer Mountain, the Serbs sought to recapture the heavily fortified town of Šabac. Violent clashes occurred on 21 and 22 August, during which Serb forces fought their way to the western approaches of the town. By 23 August, the Serbs had encircled the town and that evening they brought up their siege artillery. On 24 August, Serbian forces entered Šabac and discovered that the Austro-Hungarians had decamped the previous night. By 16:00, the Serbs reached the banks of the Sava River, bringing the first Austro-Hungarian invasion of Serbia to an end.