John McDonnell put new signing Stuart Holt straight into the squad for tonight's game against Dundalk, which saw a number of changes from Saturday's side who comfortably defeated Kildare County.
In returned Barry Prenderville, Stephen Caffrey and Michael Foley with Stephen Quigley, David Bell and Gary McPhee watching from the sidelines.
McDonnell stuck with his winning 4-3-3 formation with O'Keeffe, Doyle and Dunne spearheading the attack.
Fahey in the middle was instrumental in all the attacking moves, before been withdrawn in the second half.
Fahey had a hand of two of the goals, but the first was created following hard work from Doyle and O'Keeffe. It was the latter's pass that sent Michael Foley through on goal. He unselfishly pulled the ball square for Keith Dunne for the easiest of tap-ins.
Within 4 minutes the Saints had doubled their lead. A trademark Fahey cross was met by the head of Colm Foley who hammered the ball past Chris Bennion.
The third goal arrived 2 minutes later. Doyle sent Dunne tearing down the wing, his inch-perfect cross picked out Fahey who headed into the top corner.
Fahey came within inches of making it four. His 30 yard volley had Bennion stretching to keep the ball out.
Dundalk's first effort of the game came after 25 minutes. Peter Hynes' effort not troubling Barry Ryan in the Saints goal.
The crossbar denied Colm Foley his second of the match, before Dundalk substitute Chris Lawless beat Ryan minutes before the break.
The twelve substitutions that took place during the second half only helped slow down the game as both sides struggled to produce any noteworthy opportunities.
During the confusion Dundalk found themselves down to 10 men as they withdrew 3 players, only to replace them with 2! After noting their error, Fichra McArdle entered the playing field to balance numbers.
Former Saint Ger McCarthy rose highest to head home his side's second goal, which made for a tense final 25 minutes as the visitors went in search of an equaliser.
It didn't transpire that way and Johnny Mac's men now look forward to the visit of Limerick on Tuesday night.