Mećeva joined Yugoslav People's Liberation War in early 1941. In the first battles that took place in Aginci and Komlenac, he emerged as one of the bravest fighters of the Second Krajina Detachment. His courage stands out in battles on the mount Kozara, near Podgradci, Mrakovica and Turjak as well as near Gradina and Jasenovac. Also, he fought in conflicts on the Prijedor–Banja Luka railway.
In January 1942, Mećeva enters into the Kozara Proletarian Company, a newly formed assault unit led by Kosta Nađ and Mladen Stojanović. According to Nađ, the split between the Partisans and the Chetniks in Bosanska Krajina and central Bosnia began on 14 December 1941 in the village of Javorani. Lazar Tešanović, a schoolteacher in Javorani, influenced members of the local Partisan unit to join the Chetnik side. Tešanović then organised a Chetnik unit of about 70 to 80 men, and at the beginning of March 1942, he and his men were in the village of Lipovac. On 5 March, Mećava and his Kozara Proletarian Company led by Stojanović, Nađ, and Danko Mitrov set out for Lipovac. According to some sources, they went to Lipovac for pre-arranged negotiations with Tešanović, while other sources state that they intended to disarm Tešanović and his Chetniks. When the column of the Partisans approached the school in Lipovac, they were ambushed by Chetniks, and Mećava was wounded as well as Stojanović, who was severely wounded in the head. The Partisans remained pinned down by Chetniks fire until evening; thirteen were killed and eight beside Mećava and Stojanović were wounded. At nightfall, he and the other wounded were transported to the Partisan field hospital in Jošavka.
On 1 June 1942, the Ustaše Black Legion led by Jure Francetić attacked the Free Territory of Kozara with tanks from Dubica and Jasenovac. In this battle, Mećava entered as a sergeant of the 1st Proletarian Company of the Assault Battalion. In the battle in Klekovci, he dismantled two enemy tanks Fiat L6/40. Mećava has jumped on the first tank and liquidated tank's crew with hand grenades. Although he was hit hard from a neighbouring tank he continued to fight. When he defeated the crew of the second tank, he died of his injuries. His actions have seized two completely correct tanks on the Kadin Jelovac–Sreflije battlefront. These tanks were the first ones of the Partisans on Kozara. After the battle, Radio Free Yugoslavia repeated several times news of the heroism of the Mećava who heroically died on a hostile tank.
