From his base in Wandsbeck General Vichery personally led Jydske Regiment Light Dragoons and the French 28th Chasseur á Cherval regiment against a force of Cossacks occupying a small hamlet close to the Danish lines. Near Tonnendorf (along the road to Lübeck) they encountered enemy pickets, who were quickly driven back or captured. Vichery advanced with such a speed that the Cossack main force were taken by surprise when the Danish cavalry poured into the town where the Cossacks were in bivouac. Most of the Cossacks were captured orkilled. Some Cossacks got away by hiding in the houses, where the Danish and French horsemen couldn’t reach them without dismounting.
A wild pursuit ensued, as the Danish and French cavalry pursued the few Cossacks who had managed to get on their horses. Both Vichery and Engelsted tried in vain to control the charging body of horsemen. The disordered mob of Danish and French cavalry ran headlong into a wall of enemy cavalry (reformed Cossacks and von Dohnas black hussar regiment) 4 kilometers south of Ahrensburg. The enemy quickly counter charged the tired dragoons and chasseurs, who started to withdraw. To keep from being overrun, the Danish dragoons had to stop their retreat, do an about face and repulse enemy charges on several occasions during the retreat. At Rahlsted the pursuit evolved into a fierce melee. General Vichery and 2 Danish lieutenants became surrounded by Cossacks and had to fight their way back to the exhausted dragoons fighting like madmen in and around Rahlsted. The commander of the dragoons, Colonel Engelsted and his second in command Colonel Bonnichsen, had to keep Cossacks at bay by using their sabres. Colonel Engelsted recieved a slight concussion and had his uniform torn and pierced in several place as the Cossacks tried to kill him with their lances.
Colonel Bonnichsen (the 2nd in command) had his horse killed and was forced to fight on foot until he was surrounded and killed. A huge number of the prisoners taken by the surprise attack on the Cossacks managed to escape during the ferocious melee. The Danish and French horsemen finally found their way trough Rahlsted and on to safety, but only managed to bring along 20 prisoners. The Danes suffered 28 wounded dragoons (who they managed to evacuate to Hamburg) but another 41 dragoons were unaccounted for. Enemy losses are unknown.
La guerre, un massacre de gens qui ne se connaissent pas, au profit de gens qui se connaissent mais ne se massacrent pas. PaulV