The Battle of Le Cateau was fought on 26 August 1914

co/wikipedia
"Le Cateau was an artilleryman's battle, demonstrating the devastating results which modern quick-firing artillery using airbursting shrapnel shells could have on infantry advancing in the open. Holding their ground tenaciously against superior odds despite taking heavy casualties, by mid-afternoon, the right, then left flanks of the British, began to break under unrelenting pressure from the Germans. The arrival of Sordet's French cavalry acted as a shield for the British left flank, and supported a highly-co-ordinated tactical withdrawal despite continued attempts by the Germans to infiltrate and outflank the retreating British forces.
That night, the Allies withdrew to Saint-Quentin. Of the 40,000 Allied men fighting at Le Cateau, 7,812 were killed, wounded, or taken prisoner. Several British regiments had even disappeared from the rolls altogether.[citation needed] Thirty-eight artillery pieces (guns) were abandoned to the advancing Germans, the majority having their breech blocks removed and sights disabled by the gunners before retirement."