Two second-half goals from Conan Byrne proved the difference as St Patrick's Athletic capitalised on Galway United goalkeeper Conor Winn's red card to run out 3-1 winners at Richmond Park.
Chris Forrester and Jake Keegan traded goals in the space of three first-half minutes to leave the sides’ all-square at the break.
But a rush of blood from Winn gifted Liam Buckley's side the three points after he fouled Byrne in the penalty area, and the winger made no mistake from the spot, before adding a third in injury time.
Saints coach Liam Buckley made just one change to the side that won in convincing style in Sligo, with new signing Shane McEleney slotting into central defence ahead of Jason McGuinness, who dropped out entirely.
Galway boss Tommy Dunne also made changes at the back, with Sam Oji, Killian Cantwell and Cormac Raftery coming in for Mark Ludden, Ryan Connolly and David O'Leary leading to a reshuffle of personnel.
The game burst into life after eight minutes when Conan Byrne strode into the Galway box with nary a glance from full back Colm Horgan and cut the ball back for Chris Forrester, who had only to control the ball for one of the easiest goals he'll ever score.
Within three minutes, Galway levelled as a defensive mix-up between Saints captain Ger O'Brien and McEleney saw three Galway players race through on goal, and Jake Keegan took the responsibility on himself to stroke the ball past Brendan Clarke.
While the equaliser wasn't exactly against the run of play, it would be one of the Tribesmen's few chances in the opening half-hour as the hosts dominated possession and created a host of scoring opportunities, and Conor Winn twice denied Byrne before turning Jamie McGrath's close-range header over the bar.
An excellent long pass from Galway full-back Colm Horgan caught McEleney unaware and, had Stephen Walsh's first touch been better, would have seen the midfielder odds-on to beat Clarke in a one-on-one.
As the half drew to a close Keegan almost doubled his tally as he met Gary Shanahan's deep cross, but he glanced his header just wide, after Galway midfielder Alex Byrne showed his class at the beginning of the move with a incisive pass for Walsh.
In spite of Pats' pressure, Galway went into the break comfortably on equal terms, a fact exemplified by manager Dunne, who hardly had cause to leave his seat in an enthralling opening half.
Dunne had cause to leave his dugout 10 minutes into the second half, though, when his side were reduced to 10 men following Winn's indiscretion.
Winn's touch on Byrne may have been faint – it certainly wasn't enough to prevent the winger from reaching the ball – but referee Robert Harvey correctly it to be a foul and, with Byrne facing an open goal, the Galway man had to go.
Winn's replacement Ger Hanley had reason to sweat shortly after his introduction as Byrne – who was being roundly booed by the away support for his role in Winn's dismissal – fell in the box under the goalkeeper's attention, but referee Robert Harvey awarded a corner instead.
Galway, to their credit, refused to change their style of play and continued to force Pats into mistakes with their energetic pressing, but they failed to seriously trouble the Saints defence before Byrne bundled home his second – and Pats' third – in injury time to add an undeserved gloss to the scoreline.
St Patrick's Athletic: Brendan Clarke; Ger O'Brien, Shane McEleney, Lee Desmond, Ian Bermingham; James Chambers, Killian Brennan, Jamie McGrath, Conan Byrne, Chris Forrester; Aaron Greene.
Subs not used: Conor O'Malley (gk), Kenny Browne, Ian Morris, Sam Verdon, Darragh Markey, Jack Bayly, Morgan Langley.
Booked: Ian Bermingham (32).
Galway United: Conor Winn; Colm Horgan, Sam Oji, Killian Cantwell, Cormac Raftery; Alex Byrne, Stephen Walsh, Gary Shanahan, Paul Sinnott; Padraic Cunningham, Jake Keegan.
Subs not used: Ger Hanley (gk), Mark Ludden, Conor Barry, David O'Leary, Arron McConnell, Conor Melday, Jason Molloy.
Booked: Byrne (90+2).
Sent-off: Winn (54).
Referee: Robert Harvey.
Extratime.ie Player of the Match: Jamie McGrath (St Patrick's Athletic).