The 8th Division and its attached Indian Army units were assigned responsibility for the defence of Johor in the south of Malaya and did not see action until mid-January 1942, when Japanese spearheads first reached the state. The division's first engagement was the Battle of Muar, in which the Japanese Twenty-Fifth Army was able to outflank the Commonwealth positions due to Bennett misdeploying the forces under his command so that the weak Indian 45th Brigade was assigned the crucial coastal sector and the stronger Australian brigades were deployed in less threatened areas. While the Commonwealth forces in Johore achieved a number of local victories, they were unable to do more than slow the Japanese advance and suffered heavy casualties. After being outmanoeuvred by the Japanese, the remaining Commonwealth units withdrew to Singapore on the night of 30–31 January.