League of Ireland Premier: Derry City 0-1 Dundalk
Former Derry City boss Stephen Kenny made a winning return to the Brandywell as Dundalk grabbed a late winner in Friday's Premier Division match.
Substitute Tiarnan Mulvenna was only on the pitch a couple of minutes when he scored the winner with the game just into stoppage-time.
Mulvenna finished a fine Dundalk attack by coolly shooting past City keeper Gerard Doherty.
It means Derry stay three points behind leaders St Patrick's Athletic.
St Pat's were not in league action because of Europa League commitments, so victory would have put Declan Devine's men level on points at the top of the league.
However, they put in a disappointing display and Kenny's visitors looked the more dangerous in the second half.
They had a couple of good chances with Darren Meenan seeing his shot blocked and Richie Towell firing wide after a charge forward.
City had the best chance of the first half when Rory Patterson charged down a poor kick-out by keeper Peter Cherrie.
Cherrie redeemed himself by saving when the former Plymouth Argyle front men seemed to slightly scuff his shot.
Derry remain in second place because third-placed Sligo Rovers, last year's champions, lost 3-1 at Cork City.
Elsewhere, Limerick enjoyed a 1-0 win away to Bohemians and Bray Wanderers drew 0-0 with Shamrock Rovers.