A cracking free-kick from substitute Mark Timlin kept St Patrick's Athletic's revival going at the City Calling Stadium.
While Liam Buckley's Inchicore side are unbeaten now in four games and have moved back up into the top half of the table, the result was harsh on managerless bottom side Longford, who were the better team in the first half.
Caretaker manager Gary Cronin made three changes to the Longford side that lost 2-0 in Wexford on Friday, Tony Cousins' last match in charge prior to his resignation on Saturday.
Paul Skinner came into goal for the suspended Ryan Coulter while Kevin O'Connor returned in midfield alongside recent signing Gaius Makouta, who made his first start.
In two changes in the St Pat's team from their win over Galway United on Friday, Conor O'Malley came into goal while Graham Kelly started in midfield as Brendan Clarke and club skipper Ger O'Brien moved to the bench.
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