The order to construct the Dnieper defense complex, known as "Eastern Wall", was issued on 11 August 1943 and begun to be immediately executed. Fortifications were erected along the length of the Dnieper. However, there was no hope of completing such an extensive defence line in the short time available. Therefore, the completion of the "Eastern Wall" was not uniform in its density and depth of fortifications. Instead, the fortifications were concentrated in areas where Soviet assault-crossing were most likely to be attempted, such as near Kremenchuk, Zaporizhia and Nikopol.
Additionally, on 7 September 1943, the SS forces and the Wehrmacht received orders to strip the areas they had to abandon from anything that could be used by the Red Army to slow it down, and to try to create supply shortages for the Soviet forces by implementing the scorched earth policy.
Despite a great superiority in numbers, the offensive was by no means easy. German opposition was ferocious and fights raged for every town and city. The Wehrmacht made extensive use of rear guards, leaving some troops in each city and on each hill, slowing down the Soviet offensive.
Three weeks after the start of the offensive, and despite heavy losses on the Soviet side, it became clear that the Wehrmacht could not hope to contain the Soviet offensive in the flat, open terrain of the steppes, where the Red Army's numerical strength would prevail. Manstein asked for as many as 12 new divisions in hopes of containing the Soviet offensive – but German reserves were perilously thin. Years later, Manstein wrote in his memoirs:
After analysing this situation, I concluded that we can't keep the Donbass with the forces that we already possess, and that even a greater danger for the whole Eastern Front is being created on the north flank of the group. The 8th and 4th Armies won't be able to contain the Soviet offensive for very long.
Therefore, on 15 September 1943, Hitler ordered Army Group South to retreat to the Dnieper defense line.
The battle for Poltava was especially bitter. The city was heavily fortified and its garrison well prepared. After a few inconclusive days that greatly slowed down the Soviet offensive, Marshal Konev decided to bypass the city and rush towards the Dnieper. After two days of violent urban warfare, the Poltava garrison was overcome.