Captain Stephen O'Donnell, David McMillan, Daryl Horgan and Brian Gartland were among the goals as champions Dundalk responded in clinical fashion to last Friday's home defeat to Cork City to go back top of the Premier Division table.
Three straight wins saw an in-form St Patrick's, unchanged for the third consecutive game, start confidently at Richmond Park.
But it was a false dawn for the home faithful in the crowd of 2,150 as a defensive blunder gifted the Dundalk the lead on nine minutes. All the more ironic given St Pat's boss Liam Buckley had praised his defence ahead of the game for their having kept three successive clean sheets.
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