The Saints bounced back from a lethargic first half amid a tremendous atmosphere at the pulsating Garryowen venue.
Christy Fagan, Conan Byrne, Jamie McGrath and Graham Kelly netted for the Premier side after Lee-J Lynch’s stunner lifted the roof of the net mid way through the opening 45 minutes.
The margin of defeat was harsh on Martin Russell’s outfit, who have been promoted back to the Premier Division as champions after running away with the First Division this term.
But Pat’s picked up the pace considerably after the break to deservedly deny Limerick a double one season after Russell’s team were relegated via the play-offs.
As comebacks go, Saturday was right up there with the best of them and Buckley was magnanimous in victory on a proud night for his side in the Treaty City.
“All credit to Limerick, they have a fantastic facility here and marvellous supporters and it’s great to have them back in the Premier Division,” he said.
“I thought we were really fantastic in the second half. I think in the first half we were very good, not so good in the second half,” acknowledged Russell.
“We had two good chances to take a two-goal lead. Disappointed for the lads, but they put in a hell of a shift.
“Credit to them. They stuck at it and they played well in the second half. The fans have been tremendous. This is their biggest home gate. It shows the potential in Limerick for people wanting to get behind the football club and we have to try and do our best to try and grow that now.”
Man-of-the-match Byrne admitted that Limerick, aiming for their first cup in over a decade, caused plenty of problems in the opening half hour but reckoned they were full value for victory.
“We were disappointed with the first half but we knew we could expose their back line and Billy put in a great ball for Christy for the first goal. Thankfully, my goal came up and hit me on the chin, landed perfectly for me.
“It was nice to get that goal and Jamie killed it with the third. I think it was fully deserved over the course of the ninety minutes. Limerick really put it up to us in the first twenty five minutes but I think after that spell we came back into it.
“Their keeper made two unbelievable saves from myself and Christy. As professional footballers you can’t give up, can’t give in. Limerick have only been beaten twice by us this season in cup competition.
“To be able to come down here in front of a brilliant audience and perform the way we did is a credit to us.”
Hall, Kelly (Treacy 65), Williams, O’Connor, Duggan, Lynch, O’Conor, Russell, Greene. Kenny (Coughlan 79), Mulhall inj (O’Flynn 71)
O’Malley, Barker, Bermingham, O’Brien, Hoare, Byrne, Dennehy (Timlin 89), Desmond, Kelly, McGrath, Fagan (Corcoran 86)