Ireland captain Laura Delany said her team had missed their most obvious target in their 38-run loss to Pakistan in the Women's World T20.
Javeria Khan's unbeaten 52 led Pakistan to their highest World T20 score of 139 - a total Ireland could not match.
Ireland, the lowest-ranked team in the tournament, had targeted the match against Pakistan as a winnable game.
"To lose by 40 runs, again, we genuinely believed we could win, so it's very disappointing," said Delany.
Ranked 10th in the Women's T20 standings, Ireland upset the world number eight side Sri Lanka in their preparations for the tournament and had hoped they could repeat that performance against a Pakistan team ranked seventh in the world.
"Pakistan are closely ranked to ourselves, so that was the obvious target that we were going to go after," added Delany.
"It is so incredibly frustrating, because if we were professional, I wonder what the score would've been out there today."
A crucial missed opportunity to dismiss Javeria when she had scored just nine runs proved costly for Ireland, who did not have the batting power to match their opponents.
The Irish skipper accepted after the game that her team needed to find a way to score more runs: "We came here with a lot of belief that we could win this game but we didn't put up enough to get us over the line - 120-130 was par on this wicket.
"We just didn't have a big enough partnership. We need to look at dot balls because we didn't have enough scoring areas."
The defeat leaves Ireland bottom of Group B and they will return to the Guyana National Stadium on Thursday where they will go up against India, who have already defeated Pakistan and New Zealand and are well placed to reach the semi-finals.