A Killian Brennan penalty, Conan Byrne's double and a strike from Ciaran Kilduff sealed an emphatic win for St Patrick's Athletic on the road against ten-man Galway United at Eamonn Deacy Park.
Brennan slotted in a spot-kick after Stephen Walsh handled in the box, before Byrne doubled the Saints' lead shortly before half-time.
After the restart David O'Leary pulled one back for the hosts before Kilduff and Byrne ensured the points for Liam Buckley's charges as Galway had Alex Byrne sent off late on.
The game started slowly as both sides approached with caution. Galway carved out the opening chance seven minutes in when a pinpoint Ryan Connolly through-ball was collected by Gary Shanahan but he was denied by Pats keeper Conor O'Malley.
The visitors gradually grew into the game, however, and began to enjoy more possession, with Galway keeper Ger Hanley called into action 10 minutes later when Ciaran Kilduff chested down for Killian Brennan, who saw his effort well saved.
Twenty minutes later the FAI Cup holders hit the front when Aaron Greene's shot from distance was handled in the box by Walsh, and despite frantic protests from the United defence, referee Jim McKell pointed to the spot.
Brennnan made no mistake with his spot-kick, firing low to Hanley's left to give Liam Buckley's men the early initiative.
After enjoying the lions' share of the ball from then on, Pats doubled their lead five minutes before the interval when a wonderful move culminated in Brennan feeding Byrne, and with Galway's defence split he slotted into the bottom corner to make it 2-0.
The Saints then spurned chances to go in three ahead at the break; first Byrne's cross was headed over tamely by Kilduff and Greene fired over from another Byrne cross when he should have done better.
After the restart, however, Galway had a new spring in their step and marked their intent to find an early goal when defender Sam Oji narrowly headed wide from a dangerous Connolly free-kick.
Within four minutes Tommy Dunne's men were back in it when another Connolly free was cleared and fell to the feet of David O'Leary, who let fly from distance. The ball sailed into the net via a deflection giving O'Malley no chance.
At this point it was game on, but Pat's were still creating at the other end. James Chambers shot wide, and Chris Forrester and Greene blazed over.
On 67 minutes Pat's regained their two-goal cushion when Forrester again unlocked United's defence and Kilduff collected to delicately chip over the advancing Hanley.
This sank Galway's second-half surge and in another sweeping move Byrne magnificently made it 4-1.
Forrester was again creator before Byrne curled the ball into the top corner as the final 10 minutes began.
To rub further salt into Galway's wounds, defender Alex Byrne was sent off late on for his rash challenge on Chambers and there were few arguments with McKell's decision to hand him an early bath in front of 1,355 in Galway.