Gary Plunkett was the two-goal hero for Leitrim as they survived a late Carlow rally in Carrick-on-Shannon to retain their interest in the promotion race.
In an error-strewn first half which they dominated, Leitrim registered nine wides to one for the visitors and allowed a defensive-minded Carlow to stay in touch, with the score tied 0-6 at half time.
Leitrim upped their game in the second half, with Plunkett's first goal in the 42nd minute followed by a second seven minutes later to put the home side six points ahead.
However, the visitors responded with three unanswered points, two from the impressive Darragh Foley and one by substitute Sean Gannon, and when Danny Moran finished to the net following a well worked move in the 61st minute, Carlow were back in it.
There was a further twist when Ciaran Moran converted a penalty to put Carlow level with four minutes remaining.
And in an exciting finale, Emlyn Mulligan's free and an insurance point by substitute Brendan Gallagher in extra-time won the match for Leitrim.
SCORERS - Leitrim: G Plunkett 2-1, E Mulligan 0-6 (5f)s, N O'Donnell(2fs), B Gallagher, R Kennedy 0-2 each, M Plunkett 0-1. Carlow: C Moran, D Moran (1pen) 1-1 each, D Foley 0-5 (3fs), P Broderick (1 '45'), S Gannon, A Kelly, G Kelly, E Ruth 0-1 each.
LEITRIM - B Flynn 7; M Murphy 8, A Armstrong 7, P Maguire 8; J Rooney 8, D Wrynn 7, O Madden 7; N O'Donnell 7, S Moran 9; W McKeon 7, G Plunkett 8, M Plunkett 7; E Mulligan 8, D Moran 8, R Kennedy 7. Subs: B Gallagher 8 for N O'Donnell (55), K Beirne for D Moran (64), N Plunkett for M Murphy (BC 65).
CARLOW - C Kearney 7; C Crowley 6, C Lawlor 6, K Nolan 6; D Moran 9, S Redmond 6, G Kelly 6; B Murphy 6, S Murphy 6; A Kelly 7, D Foley 9, E Ruth 6; P Broderick 6, C Moran 7, J Murphy 6. Subs: S Gannon 7 for J Murphy (BC 36), G Power 6 for C Lawlor (BC 39), S Clark 6 for A Kelly (50), S O'Neill 6 for P Broderick (53), B J Molloy 6 for K Nolan (55), M Rennick for G Kelly (63)
REF - L Devenney (Mayo).