On 19 October, the Central Powers began the decisive second attempt to break the Allied Cobadin Fortified Line. The right wing of the forces was tasked with delivering the decisive blow but its initial assault achieved little. Only General Kolev's cavalry division, reinforced with infantry units, once again enjoyed somewhat greater success. It was in this difficult situation that the cavalry proved the advantage of its mobility and managed to overcome the heavy enemy fire on 20 October. Breaking through the main defensive line, General Kolev pushed back the Romanians and Russians towards the important village of Topraisar and threatened their flank. This and the success of the left wing of the Central Powers forces made the Allied positions untenable and they soon began a general retreat. Following his orders, General Kolev began their pursuit almost immediately, defeated the withdrawing Romanians and Russians at Constanţa, and entered the vital port city. These successes allowed the Bulgarian Third Army to advance some 80 kilometers and assume defensive positions along the narrowest part of Dobruja between the Danube and the Black Sea which in turn permitted Field Marshal Mackensen to focus on the crossing of the river at Svishtov and the operations against Bucharest that were to be carried out in conjunction with the German 9th Army.