With Second Army disintegrating around him, its commander, Alexander Vasilievich Samsonov, ordered his last remaining intact force to march north to relieve the encirclement. XXIII Corps had the army's two best formations, and they still had the combat power to completely overturn the situation in East Prussia. A hastily-summoned German force would have to hold off the relief effort or it might be the Germans offering up their swords instead of Samsonov's officers.

Russian and German accounts of this battle differ somewhat; both agree that the Neidenburg garrison held the roads south of town for some hours before giving way before the Guards' attack. According to the Russian version, the Guardsmen took Neidenburg in the afternoon; the Germans claim that their men held out until well after darkness had fallen. Either way, the attack failed to rescue Second Army, as the formations trapped to the north of town could not coordinate their own efforts to break the somewhat disorganized cordon held by the German I Corps.