The line slowly stabilized. It was helped by the arrival of the 1st Marine Brigade -- the first unit to arrive directly from the States, intact; a unit that had trained together. Indeed, it made a difference. Walker gave the Marines the responsibility of defending the Western portion of the Pusan perimeter. They stopped the North Koreans in their tracks. The Marines managed to counterattack, and achieved the first US victory of the war on this front. American troops and equipment, including the first tanks, began to pouring in, and the perimeter at Pusan held. The North Koreans attempted two major crossings of the Naktong River. The attacks were contained, and the city of Taejon was held. By the middle of September, the Pusan perimeter seemed nearly secure.