Stephen Kenny's side went down 5-2 just two days after wrapping up the league
St Patrick's Athletic have beaten newly re-crowned League of Ireland champions Dundalk 5-2 in Tuesday night's Premier Division clash at Richmond Park.
Dundalk secured their third league title in a row on Sunday and face a hectic schedule of fixtures including an FAI Cup final and Europa League commitments still to come - as well as one more league match.
They found themselves 4-0 down in Inchicore as Christy Fagan's opener and a double by Conan Byrne were added to by Ian Bermingham before half-time.
Dean Shiels and Michael O'Connor pulled two goals back for Dundalk in the second half, but Jonathan Lunney killed off any hope of a comeback by scoring Pats' fifth goal with four minutes to go.
Dundalk, who cannot be caught at the top of the table, are four point clear of Cork City with one match to go.
With Dundalk having already wrapped up the title and St Pats in sixth, six points off fourth-placed Shamrock Rovers with one match to go, tonight's fixture had little bearing on the table.
But Sligo Rovers boss Dave Robertson, whose side is fifth and one point clear of Pats, had reservations which he put out in a tweet:
Looks like Stephen Kenny & Dundalk have chucked the towel in on the League #NoIntegrity— Dave Robertson (@DaveRobertson11) October 25, 2016
That was followed up by another one:
100% mate was just hoping for a more competitive end of the season for everyone in the League, no insult intended 👍 https://t.co/xqxzicgCsm— Dave Robertson (@DaveRobertson11) October 25, 2016