On April 23, five minutes past midnight, the Chinese struck, with Baker Company on the right being the first to be hit. After pounding the rest of the battalion's positions with artillery, mortar and machine gun fire, the Chinese charged the Filipino line to the noise of bugles, whistles and gongs. They ran into a wall of fire thrown up by the 10th, with many Chinese falling to the defenders. Despite being outnumbered, the men of Able, Tank, Recon and Baker Companies in the front line resisted furiously supported by Recon's light tanks, and the howitzers and mortars of their artillery battery. The battalion's front line remained unbroken. However, the UN line broke at the Turkish sector, with the Turks withdrawing, thus exposing the right flank of the PEFTOK battalion.
Soon, intense Chinese fire was pouring into the 10th's area from the high ground at the right. To buttress the Filipino right flank, Ojeda organized and led an ad hoc force consisting of the battalion's clerks and cooks to form a defensive line which succeeded in holding off the CCF forces with help from Recon's M24s and support fire from the artillery. However, the PVA took advantage of the Turks withdrawal to go behind the 10th's lines and attack the Puerto Rican regiment, forcing it to fall back as well. With its flanks exposed, the 10th stood alone in a salient almost surrounded by a torrent of assaulting Chinese. The 10th, however, continued the stubborn defense of its three-mile front, inflicting heavy casualties on the Chinese, with Ojeda sending the men of Tank Company to stop the CCF advance.
The Chinese began to attack a platoon from Tank Company led by Lt. Jose Artiaga Jr. that had just positioned themselves on a small hill on the 10th BCT's flank overlooking Yultong. Lt. Artiaga's men refused to retreat and stood their ground, even though Artiaga would be fatally wounded in the fighting. Capt. Yap mustered and led a force to successfully rescue the platoon, though he would die in the fighting. Through sheer force of numbers, the Chinese finally succeeded in bridging a gap between Baker and Tank Companies. Capt Sanchez had been shot through the arm but he refused medical evacuation. Before Charlie Company could be fully committed, it was hit by Chinese forces that had poured through the penetrated areas. The battle had become so desperate that the Filipino staff officers at the command post, with the clerks, cooks, medics and the rest of the rear echelon troops, deployed around the headquarters area for a possible last stand, accounting for some of the Chinese who penetrated as far as there.
At dawn, Ojeda sent a surprise counterattack supported by two of the Battalion's light tanks against the Chinese, who were caught as they were regrouping following the night's fighting. As a result, the Chinese suffered heavy casualties, and were driven out of their positions. The US 3rd Infantry Division ordered the 10th to withdraw, which they successfully accomplished despite being under constant attack from the Chinese and without other UNC units to cover them.