As the German Eighth Army turned away from the Russian First Army to attack Second Army, the Russian General Staff ordered First Army to strike the exposed German rear. First Army lurched forward slowly, with only Lt. Gen. Vasili losivich Gurko's 1st Cavalry Division showing much aggression; The advance reached the outskirts of Allenstein, where it reported stiff enemy resistance.

Gurko claimed that his troopers sighted Allenstein, headquarters of the German Eighth Army, but lacked the strength to take it from the infantry that issued from the town to stop them. German accounts mention no such action, but do acknowledge that only the Russian cavalry made any attempt to bring aid from First Army to its beleaguered sister formation.