Prince Friedrich was well informed by scouts about the enemy troop line-up. The majority of the French-Saxon besiegers were camped near Riddagshausen and Broitzem, and strong artillery was positioned on the Nussberg. With Ölper, a detachment for protection against detachment of approximately 1,700 men set up. Friedrich's army left from Abbensen at around 1:00 p.m. and marched towards Ölper. Prince Friedrich had Imhoff notified of the upcoming reinforcement. At Wendezelle, which had been reached long after nightbreak, an enemy patrol was attacked, but shortly before Ölper, Prince Friedrich's vanguard got into a battle with a field guard; the besiegers were warned by the shooting. In this skirmish, the Brunswick Major General von Rothenburg fell.
Prince Friedrich ordered his men to occupy the bridge between Ölper and Braunschweig, and while the French-Saxon troops were also attacked on the left flank by a Brunswick division, the main army with Prince Friedrich at the head moved directly through the village and the surrounding hop gardens towards the enemy. The artillery that the Brunswick army had shelled since the alert was captured, the besiegers fled or went into captivity.
Prince Friedrich moved into the city of Braunschweig with cheers. The next day, the siege army of Prince Xavier withdrew to Wolfenbüttel. The Brunswick troops lost about 150 men in this battle, it is reported on the French-Saxon side that the victims were higher, and 482 men were captured.