Dundalk are on the brink of being crowned 2018 SSE Airtricity League champions after they eventually saw off Derry City at Oriel Park on Tuesday night.
Goals from Daniel Cleary, Patrick McEleney and Patrick Hoban had the Lilywhites 3-0 up and coasting at the break but an own goal by Dean Jarvis and an 89th minute goal by Ben Fisk set up a tense finish.
Stephen Kenny's side saw it out, however, to move 12 points clear of Cork City with just four games to play.
With a superior goal difference of 25, even a collapse of momentous proportions would not be enough to let John Caulfield's men back into it.
With an FAI Cup semi-final against UCD to come on Friday, Stephen Kenny made three changes to the side that beat Cork at Turner’s Cross with Daniel Cleary, Jamie McGrath and Dean Jarvis coming into the side, the latter one of three Derrymen in the Lilywhites line-up.
One of that trio was Patrick McEleney. Deployed in a deeper midfield role alongside captain Chris Shields, he was involved early on, pinging a pass in for Hoban but the striker fired wide of Ger Doherty's goal.
The expectant home crowd endured a couple of anxious moments after that with Gary Rogers happy to see Shields hack the ball away to safety after letting a corner spill from his grasp. The veteran goalkeeper did much better seconds later, tipping a well hit Rory Hale effort over the top of his crossbar.
The champions-elect took a firm grip of things after that and the opening goal came in the 16th minute.
Michael Duffy's free-kick from the right was met by Daniel Cleary who powered home his second goal of the season.
McEleney brought up Dundalk's 100th of the campaign four minutes later.
Superb hold-up play by Hoban set Duffy away on the left. His cut back found McEleney and the 25-year-old picked his spot to send a brilliant left-footed finish inside Doherty's far post.
Goal number three came in the final minute of the half. Hoban did the damage almost singlehandedly, collecting a Sean Hoare pass to easily turn inside Delap and Jamie McDonagh before curling a classy effort past the helpless Doherty.
That strike took the Dundalk hitman to 25 league goals for the season, equalling the Premier Division record set by Richie Towell, Jason Byrne and Glen Crowe, and he had numerous chances to overtake the quarter century mark in the second-half, forcing Doherty into an outrageous save with a glancing header before seeing the assistant's flag rule out another shortly after.
Derry pulled one back with 20 minutes to go. Gary Rogers did well to save from the breaking Aidy Delap but the ball rebounded off the helpless Jarvis and rolled into the net.
And Fisk, who was introduced just five minutes earlier, set up a very nervy ending when he rounded Rogers to slide home from a narrow angle but Kevin McHattie’s dismissal killed off Derry’s chances of an unlikely comeback.
Dundalk can officially confirm title number 13 when they play host to St Patrick's Athletic on Friday week.
Dundalk: Gary Rogers; Sean Gannon, Sean Hoare, Daniel Cleary, Dean Jarvis; Chris Shields, John Mountney (Dylan Connolly 61); Jamie McGrath, Patrick McEleney (Ronan Murray 61), Michael Duffy; Patrick Hoban (Georgie Kelly 85).
Derry City: Ger Doherty; Jamie McDonagh, Eoin Toal, Darren Cole, Kevin McHattie; Aaron Splaine, Rory Hale; Aidy Delap (Ben Fisk 84), Aaron McEneff (Dean Shiels HT), Ally Roy (Nicky Low HT); Ronan Hale.
Referee: Paul McLaughlin