An off-form Shelbourne once again found Kingspan Century Park the least happy of hunting grounds when they went down 2-0 to a highly motivated Monaghan United.
Shelbourne started the match fluently but were rocked on eight minutes when they slipped behind to a concession from the penalty spot.
United's Northern Ireland U-21 international Darren Meenan surged into the box after seizing a loose ball in midfield and was brought down by Alan Bryne. Meenan dusted himself off to drive an emphatic spot-kick low into the left corner.
The Shelbourne backlash was instant and Monaghan had to survive a perilous 15 minutes. James Keady shot inches wide after a forceful run and then a fabulous dribble by Gary McCabe carried him through on goal only for Kennedy to deny him with an instinctive save.
The 21st minute brought the visitors’ best effort to date, a fierce shot on the turn by Mark Rutherford from the edge of the area striking the base of the post via the fingertips of the diving Kennedy.
United gradually played themselves back into the contest after that, and a fine passing movement saw their debutant midfielder Sean Brennan flash a shot across the face of the goal with the Shels' defence at full stretch.
Shelbourne replaced centre-back Byrne with striker Philip Gorman in a half-time switch but Dermot Keely's reshuffle backfired. As his side became increasingly ragged in their play, and their travelling support increasingly impatient, United grew in confidence.
The lively Meenan struck the crossbar for the home side in the 64th minute. Gorman flashed a header wide for Shelbourne, but that was their last shot at redemption.
In the 68th minute United new boy Brennan sailed a free-kick to the back post where it was met with a thunderous header from centre-half Brian Gartland, giving Dean Delaney in the Shelbourne goal no chance.
All the visitors could muster in response were half chances for Mark O'Brien and James Keady.
With five minutes remaining Gartland sallied forward once more for United and should have had a third when clean through on Delaney, only for the Shelbourne custodian to pull off a defiant save.
Monaghan United: Kennedy; Garland, Mooney, McMahon; Whelan, Tierney, Brennan, McCrossan (Reilly 78), Clancy; Lanigan, Meenan.
Shelbourne: Delaney; Chambers, Byrne (Gorman half-time), Brennan, Hedderman; McGill (McAllister 73), O'Brien, McCabe, Keady; Rutherford, Freeman.
Referee: H Whoriskey