Richie Foran scored but was later sent-off again as title favourites Shelbourne's disappointing start to the new season met with further trouble at Oriel Park last night.
Foran, sent-off five times last season, put Shelbourne in front on 15 minutes with a fine near post header following a free-kick taken by Jonathan Minnock's.
But he showed the other side to his game when he kicked out at Dundalk defender Stephen McGuinness seven minutes after the break leaving Dublin referee John McDermott with no option but to show the striker a straight red card.
At that stage the home team should have been ahead by two goals as they were creating the better chances.
Martin Reilly was guilty of a bad miss as early as the eighth minute when he was put through on goal when Jonathan Prizeman punished a mistake by Brian Byrne, Reilly miscued his shot which trickled wide.
Four minutes later, Ger Robinson, on loan from Middlesbrough, appeared to be pulled down by Steve Williams as the Shelbourne goalkeeper failed to collect a David Crawley cross, but referee McDermott waved away appeals for the penalty.
Having then fallen behind minutes later, Dundalk admirably kept playing football and hit back on 21 minutes.
Crawley worked a throw-in with James Keddy to cross and 19-year-old Robinson headed home superbly on his debut.
Williams then prevented Dundalk from going in front a further two minutes on, stretching to his right to touch a Keddy shot out for a corner.
Having restricted Shelbourne to just one chance up to then, slack marking almost caught Dundalk out again on 34 minutes. Fitzpatrick, however, should have done better when he headed wide from Minnock's cross.
Foran might have been followed off the field by team-mate Fitzpatrick on 61 minutes for a dreadful foul on Dundalk substitute defender Bryan McCrystal who was carried off on a stretcher, but the Shelbourne striker was lucky just to receive a yellow card.
DUNDALK: Connolly; Hoey, McGuinness (McCrystal 59 mins, Connolly 61 mins), Broughan, Crawley; Prizeman (Ward 68 mins), Kavanagh, Dunne, Keddy; Reilly, Robinson.
SHELBOURNE: Williams; Heary, Gannon (McCarthy 54 mins), Hutton, Minnock; R. Baker, D Byrne, Fenlon, B. Byrne (Doherty 64 mins); Fitzpatrick (D Baker 64 mins), Foran.
Referee: J. McDermott (Dublin)
