The battalion had not completed its move, when on 19 January the troops were ordered to Ayer Hitam. The defile had become a crucial position in the British attempt to delay the Japanese advance and prevent them from cutting off the 45th Indian Infantry Brigade. 6RNR was to be reinforced by the depleted 3rd Battalion, 16th Punjab Regiment (3/16PR) and the untried 2nd Battalion, Loyal Regiment (North Lancashire) (2LR) from the 9th Indian Division as the 45th Indian Infantry Brigade retired through the 53rd Infantry Brigade positions to an area west of Yong Peng and Westforce withdrew to Labis. At 13:30 on 19 January, elements of the Japanese I Battalion, 5th Guards Infantry Regiment, Imperial Guards Division surprised a 6RNR company in Bukit Pelandok and occupied the lower slopes of Bukit Belah, commanding the Bakri road. Another 6RNR company managed to hold on at the northern slope of Bukit Belah and later took over the peak, unknown to battalion headquarters. At 05:00 on 20 January, 3/16PR was to counter-attack and recapture Bukit Belah and the northern ridge by dawn on 20 January and then 6RNR was to attack the Japanese in Bukit Pelandok covered by fire from Bukit Belah. The Punjabi attack began at 04:00, but they were mistaken for a Japanese unit by 6RNR company on the summit of Bukit Belah, who opened fire. The Indians managed to reach the peak, but before it could be consolidated, a Japanese attack forced the British and Indian troops off the ridge with many losses, including the Punjabis' commander. The attack on Bukit Pelandok was repulsed and the British and Indian troops were moved to between the defile and causeway with the left flank covered by 2LR.