Kurtis Byrne came from the bench to break Limerick's resistance and give Dundalk a 2-1 win at Oriel Park - their first victory of the season.
Byrne popped up in the 79th minute - nine minutes after coming on for David McMillan - to head home from six-yards after Patrick Hoban's effort was saved by Shane Cusack.
After a quiet opening to the game, Limerick took the lead after 15 minutes when Shane Tracy's 40-yard free-kick was inexplicably dropped and carried over the line by Dundalk goalkeeper Peter Cherrie.
Dundalk hit back and David McMillan and Daryl Horgan both went close before the Lilywhites equalized four minutes before the half-time whistle.
Again, it was a goalkeeping error which led to the goal as Cusack completely misjudged Mark Rossiter's cross from the right and Hoban was left with a simple header.
The Super Blues squandered a great opportunity to go back in front after 47 minutes when Rory Gaffney took advantage of a defensive slip to go through on goal but Cherrie redeemed himself to save with his feet.
Dundalk turned the screw after that and Horgan should have put them 2-1 ahead when he met a Mark Rossiter cross at the back post but he turned the effort wide.
The winner arrived with just 11 minutes when Byrne reacted sharply to head home despite the best efforts of the covering Shane Folan.
Dundalk should have made the game safe with further efforts from Horgan and Hoban, and Richie Towell hit the post with an audacious late effort, but they saw the game out to record their first league win over the Munster men since 2008.
DUNDALK: Cherrie; Rossiter (Gannon 63), Boyle, Gartland, Massey; Meenan, O'Donnell, Towell, Horgan (Mountney 89); Hoban, McMillan (Byrne 70).
LIMERICK: Cusack; Kelly, Whitehead, Folan, Costelloe; McGrath (Feeney 82), Tracy, Nzuzi (Ayemang 81), Hughes, Coughlan (Rainsford 54); Gaffney.
Referee: Paul McLaughlin (Monaghan).