Flamengo claimed a crucial 1-0 away victory over arch-rivals Atletico Mineiro in the first leg of their Brazilian Cup round of 16 tie at the Mineirao Stadium. The match result gives the Rio de Janeiro giants a slender but precious advantage heading back to the Maracana for the second leg. In a tense and tactical Clássico Nacional, the only goal came from a moment of individual brilliance or a set-piece in the second half, breaking the deadlock in a match of few clear chances. Flamengo's defense, led by their experienced goalkeeper, held firm under late pressure from Atletico, including a vital save in the dying minutes. The win puts Flamengo in the driver's seat for the quarter-final berth, while Atletico Mineiro now faces a difficult task to overturn the deficit away from home.