Level at half-time against joint record title holders Portlaoise - and playing in Portlaoise's backyard at MW Hire O'Moore Park - the underdogs roared to a famous win, outscoring the hosts 1-6 to 0-1 in the second-half.

A bad evening for Portlaoise, who didn't score from play in that second-half, ended with 53rd and 62nd minute dismissals for Kieran Lillis and Conor Boyle.

It's a case of back to the future for Eire Og who won five Leinster titles in the 1990s, dominating the provincial scene between 1992 and 1998.

The current team have a bit to go to equal those achievements but this was a huge win all the same, coming after a surprise quarter-final defeat of Kildare's Sarsfields.

Bar a 10-minute in the lead up to half-time when Portlaoise were on top, it was all Eire Og who turned in an expert display of counter attacking football.

Chris Blake was their lead marksman and he fired 1-4, 1-3 of which came from play, while Niall Quinlan scored three important points from frees after his half-time introduction.

Eire Og came armed with confidence and momentum and surged 1-3 to 0-1 ahead after just 15 minutes with Blake hitting the net inside the opening 60 seconds.

Portlaoise, who beat St Pat's of Wicklow on penalties to reach the last four, fought back to level terms by the 19th minute thanks in part to a Lillis goal.

The sides were deadlocked at 1-5 apiece at the break though Eire Og had failed to convert a 26th minute penalty and proceeded to dominate the second-half.

They scored the first three points of the second period and were always in control while Portlaoise, in contrast, racked up the wides and could only muster a Brian McCormack point from a free.

Lillis walked for his second yellow card in the closing minutes and Boyle's frustrations got the better of him too in stoppage time.

The game was over by that stage as Ross Dunphy started and finished a flowing Eire Og move in the 60th minute to grab their second goal.

Eire Og scorers: C Blake (1-4, 1 free), R Dunphy (1-1), N Quinlan (0-3, 3 frees), J Lowry, C Hulton, D O'Brien (0-1 each).

Portlaoise scorers: Scorers: K Lillis (1-1), B McCormack (0-2, 1 free), B Carroll, G Dillon, C Boyle (0-1 each).

Eire Og: R Keating; J Lowry, M Fitzgerald, B Kavanagh; R Mahon, M Furey, P McElligott; S Gannon, E Ruth; R Dunphy, D O'Brien, C Hulton; C Blake, J Morrissey, C Mullins.

Subs: N Quinlan for Mullins h-t, D Hayden for Hulton 51, R Denieffe for O'Brien 62, K Chatten for Mahon 65.

Portlaoise: G Brody; G Saunders, F Flanagan, D Seale; D Holland, Chris Finn, P Downey; K Lillis, C McEvoy; B Carroll, C Boyle, B Glynn; G Dillon, B McCormack, R Maher.

Subs: D Larkin for Downey h-t, Colin Finn for Holland 43, C Rogers for Maher 48, R McEvoy for Flanagan 54.

Ref: P Maguire (Longford).