The Germans had heavily bombarded Russian defences. On 20th August the Russian troops were forced to surrender, with their inner defences vulnerable.
Citation:
Editors. "Germans take Novo-Georgievsk".
The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=12320, accessed 21 May 2013.]