During the early phase of the Battle of Passchendaele, Andrew's battalion was engaged in fighting around the village of La Basseville, a few kilometres southwest of Messines. Originally captured by the New Zealanders prior to the battle on 26 July, the village had been re-taken by the Germans the next day. Under cover of an artillery barrage, the Wellingtons began an advance towards the village. Andrew was tasked with leading two sections to destroy a machine-gun post. During the advance, he noticed a nearby machine-gun post that was holding up the advance of another platoon. On his own initiative, he promptly diverted his force and removed the newly spotted threat with a flanking attack. He then led his men to the original objective. Despite continuous gunfire, he and his men captured the machine-gun post. While most of his men withdrew with the gun, Andrew and another man continued to scout further forward. Coming across another machine-gun post, the two men destroyed it before returning to their lines with information on the increasing numbers of Germans in the area. During his foray, Andrew received a flesh wound to his back.