Carlow 3-11 Louth 2-24
Ryan Burns blasted 1-07 in Portloaise as Louth cruised to a 10-point Leinster championship victory over Carlow, setting up a battle Royal with old rivals Meath.
But the scoreline flattered the Wee County, who led by just two points inside the last 10 minutes before finishing with a flourish that included late goals from Burns and Anthony Williams.
It was reminiscent of Louth's strong finish against Antrim in the Allianz league Division 4 final when they stole victory with a similar late blitz.
Their reward this time around is a 12 June provincial quarter-final clash with neighbours and great rivals Meath, a repeat of the 2010 final.
Midfielder James Califf had a strong game for Louth too and weighed in with five points as Colin Kelly's side delivered on their favourites tag.
Carlow lost by 13 points when the sides met in the league though did beat Louth the last time they faced off in the Championship, a surprise one-point win in 2011.
Still, Louth approached the game as considerable favourites after capturing spring silverware and quickly set about putting daylight between the teams.
Five points in a row moved them into a 0-05 to 0-01 lead after 11 minutes and they led from there all the way.
Declan Byrne, one of two Louth starters who were involved in their 2011 Championship defeat to Carlow, was among the scorers.
Carlow did come back into the game with a four-point burst and Brendan Murphy, their ex-Australian Rules player at midfield, came strongly into the game.
But the closest they got to Louth was a two-point deficit after 27 minutes, 0-07 to 0-05, and the north-east outfit hit the throttle again approaching half-time.
This time the 2010 provincial finalists landed four points in a row including two from Jim McEneaney to open up a 0-11 to 0-06 lead at the interval.
Louth were always in front throughout the second-half but timely Carlow goals from Chris Blake and Darragh O'Brien in the 41st and 55th minutes meant the Barrowsiders were never out of it.
Turlough O'Brien's side trailed by just two points with 62 minutes on the clock and were in with a shot of progression themselves.
But Louth finished strong and 2-02 without reply in the closing stages sealed a big win.
They were 13 clear deep into injury-time following Burns' 70th minute goal and Williams in the 74th.
Carlow were awarded a penalty and Paul Broderick converted it with the last kick of the game.
Scorers - Louth: R Burns 1-07 (0-05f), J Califf 0-05 (0-03f); A Williams 1-00, J McEneaney 0-03, D Maguire 0-02, D Byrne 0-02, C Grimes 0-02, J Stewart 0-01, G McSorley 0-01, R Holcroft 0-01 Carlow: D Foley 0-05 (0-05f), C Blake 1-00, P Broderick 1-01 (1-00 pen, 0-01f), D O'Brien 1-00, B Murphy 0-02, B Kavanagh 0-01, J Murphy 0-01, S Gannon 0-01
Louth: C Lynch; K Toner, P Reilly, P Rath; D Maguire, D McMahon, A Williams; J Stewart, J Califf; D Byrne, J McEneaney, C McKeever; B Duffy, R Burns, C Grimes
Subs: R Moore for Duffy, G McSorley for McKeever, R Holcroft for McEneaney, J Bingham for McMahon BC.
Carlow: R Molloy; B Kavanagh, D St Ledger, K Nolan; H Gahan, J Murphy, G Kelly; B Murphy, S Gannon; D Lunney, D O'Brien, A Kelly; P Broderick, D Foley, C Blake (1-00).
Subs: Brian Murphy for Lunney, G Power for J Murphy, D Smithers for Blake, E Finnegan for Kelly.
Referee: Noel Mooney (Cavan).