Otavinho scored in the 89th minute to draw Internacional level, after Atletico PR midfielder Joao Paulo saw red five minutes prior as the momentum swung the way of Dunga's men.
Atletico PR substitute Fran Merida was also dismissed late on, earning his marching orders deep into injury time, which leaves head coach Vagner Mancini with a selection headache for the second leg in Curitiba.
Earlier, it was a dream start for Atletico as Paulo Baier score on five minutes to stun the home fans at the Estadio do Vale.
Goias were the only side to emerge out of the quarter-final first legs with a lead, as they came from behind to beat Vasco da Gama 2-1 at home.
Vasco took a lead in just the second minute when Edmilson found the back of the net, only for the hosts at Estado de Goias to equalise from the penalty spot, with Walter dispatching of the spot kick.
The sides remained all square until Roni put away an assist from Walter on 74 minutes, to give Goias the advantage at the midway point of the final-eight contest.
Botafogo were forced to arrest a deficit to earn a 1-1 draw at home to Flamengo, with Edilson's goal cancelling out Andre Santos' opener, while Corinthians were held 0-0 at home to Gremio.
