Having had their Europa League place given to St Patrick's Athletic amid considerable rancour last month, goals from Ismahil Akinade, Zack Elbouzedi and Aaron Drinan gave Waterford some consolation with the deserved three points from this SSE Airtricity League Premier Division clash at Richmond.
Waterford may have failed to meet UEFA criteria for a license to play in Europe but they proved the far more clinical side in front of goal here with three well-taken second half strikes.
St Pat's shaded a tight opening and would have been ahead but for a stunning save from Waterford keeper Matt Connor 19 minutes in.
Jamie Lennon's diagonal ball picked out the run of skipper Ian Bermingham whose first time volley was put out for a corner by Connor's superb reaction save with his feet.
Minutes earlier Waterford striker Drinan, who scored both goals in a 2-0 win for Blues when the sides met at the RSC back in March, might have done better with the visitors' first attack of the game, slicing wide after winning a header with Dave Webster.
Drinan was proving a right menace for the home defence, again getting the better of Webster but not awarded a free kick for what looked a fairly blatant obstruction.
But the Republic of Ireland under-21 attacker should have given his side the lead on the half hour when he did elude the St Pat's defence.
Played in one-on-one with Brendan Clarke by John Martin, Drinan looked set to score only to wastefully scuff his shot wide of the far post.
That did lead to Waterford enjoying their best spell of possession in the first half as St Pat's laboured to regain their early initiative.
Harry Kenny's side did reassert themselves from the resumption, Bermingham again getting free on the left to head wide from a Simon Madden cross early on.
Waterford made two changes just before the hour that changed the game as both were involved in their taking the lead on 63 minutes.
Elbouzedi's ball was cleverly flicked through by Karolis Chvedukas for Akinade who confidently drilled his right-foot shot past Clarke.
Another well-worked move breached the St Pat's defence six minutes later.
This time Cory Galvin threaded Elbouzedi through and the Ireland under-21 winger found the net with a composed finish.
St Pat's were inches from getting a goal back on 74 minutes.
Damien Delaney allowed a cross to drop in behind him. Gary Shaw's shot was parried by Connor with defender Rory Feely's attempted clearance hitting a post before being cleared.
Waterford then soaked up St Pat's late pressure to strike for their third goal on the counter-attack with Drinan finishing well with a low drive on 88 minutes.