Ireland were unable to defend 154 for five as Oman marked their debut in a major International Cricket Council (ICC) event by sealing victory with two balls to spare after needing 14 runs off the last over.
“It's very disappointing and hard to take but to a large extent, it's still in our own hands,” Porterfield told British media.
Ireland face full-member nation Bangladesh in Dharamsala on Friday before they take on the Netherlands at the same venue two days later. Only the group winners will progress to the Super 10 stage.
“We've got to address it come Friday and I think that's more mental than anything... as long as Oman lose a game, then it's still in our own hands,” Porterfield said.
“It'll come down to run-rate. We've got to win two games, but that is what it is... and we're going to have to keep an eye on it.”
Original source: Ireland still hopeful despite Oman loss