The forces landing at Caba and Agoo were to press south toward Damortis and Rosario. Two roads would be used: the coastal highway to Damortis, and the partially surfaced road which paralleled the Aringay River and led to Rosario. Once at their objectives, these troops were to assemble and "prepare to advance" toward the bank of the Agno River, the first formidable obstacle to a force moving south from Lingayen Gulf to Manila.

Even before the Japanese had entered Sison that afternoon, General Wainwright had telephoned MacArthur's headquarters at Manila. After explaining that further defense of the Lingayen beaches was "impracticable," he requested permission to withdraw behind the Agno River. This request was readily granted. Believing that he could launch a counterattack if he had the Philippine Division, then in USAFFE reserve, Wainwright also asked for the division and for permission to mount an attack from the Agno. He was directed to submit his plans. "I'll get my plans there as soon as possible," he replied, but asked for an immediate answer on whether he would get the Philippine Division. After a slight delay, he was told that his chances of securing the division were "highly improbable." Nevertheless he began to make his plans for a counterattack.³⁴

The action of 24 December placed the Japanese in position for the final drive toward the Agno River. At about 0500, with the 4th Tank Regiment in the lead, the Japanese made contact with the 26th Cavalry outposts north and west of Binalonan. Although the Scouts had no antitank guns, they were able to stop the first attack. The tanks then swung west to bypass the American positions, leaving the infantry to continue the fight for Binalonan. By 0700 the 26th Cavalry had blunted the assault and inflicted many casualties on the enemy. Pursuing their advantage, the Scouts counterattacked and the Japanese had to send in more tanks to stop the 26th Cavalry. Even with the aid of tanks, the Japanese made no progress. Sometime during the morning the 2d Formosa joined the attack, and the cavalrymen found themselves in serious trouble. Too heavily engaged to break off the action and retire, they continued to fight on.