Romanian frustration with having to endure this bombardment boiled over, and on 22 September General Popovici ordered his 13th Division to take the heights at Veresmart (Roșia/Rothberg), east of Nagyszeben.

Although Popovici's attack failed in its immediate aim, it succeeded in worsening the strategic situation of the Central Powers, driving a wedge between the two divisions of a German-led Cavalry Corps.

Konrad Krafft von Dellmensingen's Alpine Corps Division was to act as an anvil, seizing the Red Tower Pass in order to block a Romanian retreat.

Hermann von Staabs's Corps, assembling northwest of Nagyszeben, was to act as a hammer, driving southeast towards the mouth of the Red Tower Pass at Nagytalmács (Tălmaciu/Talmesch).

However, reconnaissance by the German Alpine Corps revealed that it was possible to bypass his western flank, on foot, through the mountains, then reach and cut off the Romanian line of retreat.

This made Popovici's corps the most tempting target, and von Falkenhayn stressed as much: all else was secondary to striking a decisive blow at Nagyszeben.

On 26 September, Lieutenant-Colonel Toma Popescu, a staff officer carrying messages from the 1st Army to Popovici, arrived south of the Red Tower Pass and created a makeshift force which he used against the Alpine Corps.

Following his victory against the Romanians at the First Battle of Petrozsény (18-22 September), Falkenhayn pulled out most of the German forces from that sector of the front - 4 battalions out of 6 - leaving only two, along with two batteries.

[37] During the 27th, German and Hungarian regiments slowly made their way through Dolmány (Daia/Thalheim), Bongárd (Bungard/Baumgarten) and Hermány (Cașolț/Kastenholz), also capturing the 601 meters-tall Grigori height (the northernmost Romanian position, northeast of Nagyszeben).

As fighting on the northern front intensified, the Romanians became aware of the German forces in their rear and undertook some ineffective measures to drive them out.

General Popovici sent his 48th Infantry Regiment from the north, but the Jägers - positioned in the hills above Kaiserbrunnen - decimated the unit with machine-gun fire.

Lieutenant-Colonel Toma Popescu, a staff officer of the 1st Army carrying messages for Popovici, came across the Bavarian Guards of Prince Heinrich's III Battalion at the Câineni bridge.

Under the leadership of a Police Sergeant and an army straggler, the Romanians put the Germans under fire, with such success that the Bavarians became confused and started searching the east side of the pass.

Popovici sent 5 battalions south and managed to drive the Alpine Corps Jägers from the northern part of the defile and out of most of Râu Vadului as well.

The situation continued to deteriorate for Popovici, when the XXXIX Corps started making progress against the main Romanian positions, driving his beleaguered battalions back into the mouth of the Red Tower Pass.

As von Falkenhayn himself noted: "Seldom in my life, which had not lacked dramatic moments, had I awaited the outcome with such suspense as on the morning of 29 September.".

[46][47][48] Popovici had given the strictest orders for silence, but once the Alpine Corps spotted the Romanians and put them under fire, his panicked soldiers shouted and cursed at their animals, which bolted.

"The cries of the wounded, the machine-gun and rifle fire, the bellowing of the animals and the roaring waters of the Olt all echoed in the narrow passage, adding to the hellishness of the scene.".

Pressure on the extreme western flank of the Austro-Hungarian 1st Army drove back a weak Hungarian cavalry detachment and the battered 71st Division.

Falkenhayn was alarmed to receive a message from the usually aggressive Curt von Morgen - whose I Reserve Corps commanded this flank of Arz's 1st Army - that he viewed a further retreat as almost inevitable.

However, the Romanians resumed their offensive during the afternoon of that same day, attacking the 1st Cavalry Division north of the Olt and pressing it back to the heights east of the Hortobágy.

The German reserve, not required at Nagyszeben, was swiftly deployed with heavy motor wagons through the Hortobágy Valley to the aid of the heavily engaged Schmettow Cavalry Corps.

[54] During its advance on the 28th, the Romanian 2nd Army gained several settlements, most notably the village of Nagysink (Cincu/Großschenk), a district (járás) capital within the Nagy-Küküllő County.

Other losses included 10 locomotives with 700 loaded railway wagons (300 of small arms ammunition, 200 of artillery munitions and 200 filled with baggage), 70 cars and trucks, a hospital train and a paymaster's supplies.

[68] In consequence, the Romanian troops which defeated the first Central Powers offensive south of the Red Tower Pass in late October were those beaten at Nagyszeben in September.

By 26 September the Alpine Corps, in a long flanking march, had pushed forward to the Rotenturm Pass in the rear of the enemy, whereupon the main body of the Ninth Army attacked on both sides of Hermannstadt.

However, the Rumanian main forces moved too late, and could not prevent the complete overthrow of a part of their army at Hermannstadt.John Buchan, historian:[74] The retiring troops lost heavily, but the amazing thing is that their losses were not greater.

The Germans claimed no more than 3,000 prisoners and thirteen guns, and the main booty was laden wagons and rolling-stock intercepted on the Hermannstadt railway.

[76] Thus, while a general named Manolescu did command the two Romanian divisions at Nagyszeben, he had been replaced for over a week by Popovici by the time the battle started.

Some sources may erroneously refer to the Central Powers attempt at annihilating the Romanian forces north of the Red Tower Pass as a success.