With the Allied beachhead slowly but constantly expanding, more and more troops were able to land in France and enter the fight. For the first five days of the invasion, the 6th Airborne Division had been in sole charge of the bridgehead across the River Orne, but on the 11th June they were joined by the 51st Highland Division, who gradually began to assume responsibility for the southern flank and so relieved a great deal of pressure on the Airborne men. In addition one of their battalions, the 5th Battalion The Black Watch, was placed under the command of the 3rd Parachute Brigade, in view of the fact that they were responsible for holding a large area and were bearing the brunt of severe enemy attacks.
In the early hours of the 11th June, the 5th Black Watch arrived in the vicinity of the 9th Battalion. Their "D" Company relieved "C" Company at the Chateau St Côme, whilst the remainder, at 04:30, proceeded to mount an attack upon Bréville from the south-west. All of the mortars of the 9th Battalion and the 5th Black Watch, joined by the guns of the 51st Highland Division, pounded Bréville as the Highlanders made their way forward. When this barrage ceased, both the advancing and supporting companies came under withering machine-gun and mortar fire, which quickly stopped the attack in its tracks. With an estimated three hundred casualties, the 5th Black Watch retired to the Chateau St Côme where they dug defensive positions in anticipation of a counterattack.
There were no other major incidents on the 11th June, but at noon on the following day the positions of the 3rd Parachute Brigade were subjected to an intense mortar and artillery bombardment. At 15:00, a strong force of infantry attacked the Canadians at Le Mesnil, whilst another, supported by six tanks and self-propelled guns, fell upon the 9th Battalion and 5th Black Watch. The initial blow landed amongst the Highlanders at the Chateau St Côme. Very quickly, all of their anti-tank guns were put out of action, and the Battalion struggled desperately to hold the Chateau once the enemy tanks began to fire directly into it. Ground was gradually surrendered as elements of the 5th Black Watch fell back towards the 9th Battalion in the Bois de Mont.
The 9th Battalion were themselves under similar pressure from infantry and armour at this time. "A" and "B" Companies were having difficulty in combating the tanks, but eventually several PIAT rounds inflicted damage and forced them to pull back, along with their accompanying infantry who disappeared into nearby woodland. Although this attack had been fought off, the situation was not in the least promising as the defence had been severely tested and the 9th Battalion was running low on ammunition. Lieutenant-Colonel Otway sent a message to Brigadier Hill to ask for aid. Hill knew that Otway would not make such a request unless he was in serious difficulty and so he immediately consulted Lieutenant-Colonel Bradbrooke about the possibility of assistance. Despite the fact that the Canadians were having great problems of their own at the time, with tanks infiltrating into awkward positions and searching for a way through their defence, Bradbrooke felt that he could spare his reserve force of "C" Company, which Hill personally led in the direction of the 9th Battalion.
When they arrived, "C" Company were faced with an untidy situation. The woodland was being fiercely disputed between the 5th Black Watch and the Germans, whilst the Chateau St Côme was in enemy hands, although a single group of Highlanders were still offering determined resistance from one of the outbuildings. Major Hanson led his Canadians forward and won back the Chateau, and after hard fighting the Germans abandoned the attack with the positions of the Brigade restored to their original state. The 3rd Parachute Brigade had survived the 12th June, but their ability to withstand another attack of this magnitude was questionable.