The pain of Friday's defeat at the same venue was still raw yesterday as the Scots came to terms with the fact they can no longer automatically qualify for the 2015 World Cup.
They had looked well placed until a double defeat to Afghanistan this year raised doubts. Two wins against Kenya in July rekindled hopes and they went into this weekend's double-header against their old Celtic rivals knowing double success would pile the pressure on the Afghans.
But Scotland can no longer achieve the second place they needed in the eight-team World Cricket League and must gear up for a further qualifying tournament in New Zealand in January when the final two World Cup places will be up for grabs.
The process starts today as Mommsen, thrust into the captaincy due to Kyle Coetzer's wrist injury, recognised. "Friday was as big a disappointment as I can remember, especially because of the way we had dragged ourselves back into the contest only to fall at the final hurdle," he said. "But we have to put the disappointing aspect of the result behind us and take the positive parts of the performance because we have another big ODI to prepare for.
"Every ODI is important because they all count towards ranking points and the higher our position, the better our seeding will be for the tournament in New Zealand."
With Afghanistan favourites to join Ireland as automatic qualifiers, the Scots will again come up against the remaining five sides in the World Cricket League - Netherlands, UAE, Kenya, Namibia and Canada. They will be joined by Hong Kong, Nepal, Papua New Guinea and Uganda.
Mommsen added: "We know from our experience in the World Cricket League how evenly matched the sides are. That goes for ourselves and Ireland as we proved on Friday and by beating them in the previous meeting in 2011."
It is Scotland's failure to get over the finishing line that rankles with Mommsen and his team-mates, who are privately disgruntled at the widely held belief that the current Ireland team are streets ahead of them. The evidence on Friday suggested otherwise but the one area where the Irish appear to have a clear edge is in their winning mentality and until the Saltires find a way of beating their rivals consistently, Mommsen knows he and his team-mates must endure the jibes.
"We know there is not much of a gap between us and Ireland but we have to do our talking on the itch. Despite Friday's disappointment it's great we have a chance to bounce back straight away and hopefully we can do that."
Coach Pete Steindl was yesterday assessing the mental and physical state of his squad after Friday's arduous contest and the three players who took no part in that match - Gordon Drummond, Gordon Goudie and Craig Wallace - will all come into contention.