Using some potential theory tools and the Schauder fixed point theorem, we prove the existence and precise global behavior of positive continuous solutions for the competitive fractional system(−Δ|D)α/2u+p(x)uσvr=0,(−Δ|D)α/2v+q(x)usvβ=0in a boundedC1,1-domainDinℝn (n≥3), subject to some Dirichlet conditions, where0<α<2,σ,β≥1,s,r≥0.The potential functionsp,qare nonnegative and required to satisfy some adequate hypotheses related to the Kato class of functionsKα(D).