Imperial cavalry under Raimondo Montecuccoli and Johann von Werth launched a surprise attack on the Swedish camp of Carl Gustaf Wrangel and inflicted 380, or more than 1,300, losses on them in exchange for 200–300 casualties.

The advance of the relieving Imperial army through western Bohemia had been delayed by waiting for the arrival of general Johann von Werth's defecting Bavarian troops, so that the Swedish general Carl Gustaf Wrangel had sufficient opportunity to prepare the defense of the southern approaches to Eger.

On 8 August 1647 the Imperial relief force retired to the south and encamped at Křimiz and Tuschkau on the Pilsen plain.

Ten cavalry regiments and 1,500 infantry now took up positions between the villages of Schlief, Wieschka, Hangendorf and Goldwag on the other side of the Michelsberger Bach.

This letter of protection was an enormous reassurance for the citizens of Plan, as the Swedish army was far from military discipline and order after the death of King Gustavus Adolphus.

Fearing the loss of western Bohemia, he ordered his army to march north and attack the Swedish forces.

An advance division, to which Johann von Schwanberg belonged, fought with Swedish troops between Plan and Triebl near the Spittelteich pond.

The results of the investigation soon made the Imperial troops aware of Wrangel's positions and it was obvious that Triebl Castle, which served as an advanced observation post, had to be captured.

The shelling of Triebl began on 18 August at around 2 p.m.[5] The Swedish crew found themselves helpless in the face of the bombardment, as they only had 2 field cannons of smaller caliber, with which one could not reach the long-range guns of the Imperial armed forces.

The Swedish ensign waited in vain for help, because the deep and impassable bottom of the Michelsberg brook makes it impossible to intervene quickly.

Montecuccoli and Werth were immediately determined to seize the opportunity and storm the Swedish positions, perhaps even the main camp.

[5] A local woman, the wife of the village judge von Triebl, led the armed forces under the protection of the wooded gorge into the bottom of the Michelsberg brook before daybreak.

During the advance, the imperial troops captured a large amount of war material and personal property of the Swedish soldiers.

He succeeded in bringing the broken regiments to a standstill and organizing a counterattack in which the heads of the Imperial troops who had been chased back were repulsed.

After two hours the Swedish troops succeeded in gaining a foothold on a broad front, but the Witkopf and Alexander Lilien regiments suffered heavy losses.