The losing bonus point garnered by the Ulster sides was enough to edge out their Leinster rivals who needed to run up big wins to have any hope of advancing.
It meant they joined Banbridge as the side to progress from Pool B and they go on to meet Monkstown in the semis.
Banbridge eased to top spot in the Pool with a fifth straight win, seeing off Glenanne 2-1 in a low-key affair while Railway Union landed a 4-2 win in Cork against C of I.
In Pool A, Monkstown dropped points for the first time in the competition but still managed a 2-2 against Annadale.
UCD confirmed first place in the women’s Pool B with a strong 3-0 win over Ballymoney, a result that eliminated the Co Antrim side while allowing Ards to sneak through, too, to the semi-finals. Ards picked off a 2-0 win over Lurgan.
It left Old Alex unable to breach the top two but they did close out their IHL campaign with a 1-0 win over Cork Harlequins.
Loreto and Railway Union eased into the semi-finals of the Irish Hockey League, rendering Pegasus’ efforts in Limerick to grind out a 3-2 win over Catholic Institute not enough. Elsewhere, Ulster won back the men’s junior interprovincial title following wins over Munster (3-0) and Connacht (6-4).