The global superstars will go head to head over a two-game World Cup qualification playoff, with only one man and one nation able to advance to next summer's showpiece tournament.
The 32-year-old Ibrahimovic believes the Scandinavians are more deserving of a place in the finals.
"We have had tough matches during qualification but this has only stimulated us," the Paris Saint-Germain striker told reporters. "Portugal are probably favorites given their team and their individuals, but we came second in a group featuring Germany and we deserve to go to Brazil more."
The first leg will take place at Benfica's Estadio da Luz on Friday night before the two sides square off again in Stockholm four days later.