The Proteas suffered afive-run defeat to Sri Lanka in their opening match of the tournament in Bangladesh, with Duminy top-scoring with 39 in a losing cause.
With only two teams qualifying from each pool of five, Duminy has conceded that South Africa will now likely have to win all of their remaining three group-stage games to make it to the last four.
"There's always going to be that added pressure on us now, depending on how other results go we're probably going to have to win all three," he told reporters.
"We want to make sure that we give ourselves the best chance in this tournament and that unfortunately means winning the last three games. That's what it is and we're going to have to play accordingly."
South Africa are next in action against New Zealand in Chittagong on Monday.