Early goals key for Limerick
Limerick were missing dual players Stephen Lucey and Mark O'Riordan, who were in action for the hurlers against Antrim in Parnell Park, but forward Ian Ryan stepped up the mark in their absence and his contribution of 1-7 led the home side to a superb win.
Offaly will rue a string of wides - they kicked nine alone in the first half - but Limerick deserved their win, with Ger Collins scoring the all-important goal with seven minutes remaining.
Offaly actually established an early lead, Niall McNamee pushing them 0-2 to 0-1 ahead after 10 minutes. However, two goals in a three-minute spell gave the home side the kind of start they would have dreamed of.
Ian Ryan grabbed their opening goal on 12 minutes and then turned provider for Seamus O'Carroll two minutes later.
Ryan then added three more points from play to give his side a 2-4 to 0-2 lead by the mid point of the first half.
But Offaly began to establish a foothold in midfield and four points from placed balls, all expertly dispatched by veteran Ciarán McManus, brought Tom Cribbin's side right back into the game.
Offaly may have kicked nine wides in the first half, but Niall Darby did find the target from play to reduce the deficit to just three at the break, 2-5 to 0-8.
Limerick's Ryan brought his tally to 1-4 on the retsart, before McNamee and substitiute Pádraig Bracken had the gap back to two as Offaly looked as if they were going to overtake a tiring home side.
However, Offaly's shooting let them down badly and two points was as close as they would get in the game, despite Ciarán McManus's continued excellence from placed balls.
The crucial score came in the 63rd minute, as Limerick turned over ball in midfield and Stephen Kelly fed Collins, who smashed the ball home from 13 yards.
Eoin Hogan and Ryan tapped over late points for Limerick as they added a late coat of gloss to the scoreline and, crucially, sealed their place in Round 3.