The inexperienced Americans did not clear German positions as effectively as they might have. This forced the advancing Australians to fight for the ground that the Americans were planned to have already taken. In the confusion of battle, some American pockets that had been left without effective leadership willingly went along with the Australians as they advanced and there are documented accounts of soldiers from both nations fighting alongside each other in ad-hoc mixed outfits. The Battle of St. Quentin Canal was a pivotal battle of WWI that began on September 29, 1918 and involved British, Australian and American forces in the spearhead attack and as a single combined force against the German Siegfried Stellung of the Hindenburg Line. Under the command of Australian general Sir John Monash, the assault achieved all its objectives, resulting in the first full breach of the Hindenburg Line, in the face of heavy German resistance and, in concert with other attacks of the Great Offensive along the length of the line convinced the German high command that the writing was on the wall regarding any hope of German victory.