Shamrock Rovers ended Shelbourne's unbeaten start to the Premier Division season with a 4-0 win in a game that saw both teams down to ten men.
Gary Twigg put Rovers ahead from the spot early on after Dean Delany was sent-off for fouling Billy Dennehy. Stephen Hurley's blind back pass resulted in a comical own goal as Rovers went two ahead. Ronan Finn's stunning long-range strike made it three before the break.
Aaron Greene punished poor defending from Ian Ryan on 73 minutes to complete the scoring.
President Michael D Higgins and Ireland international Kevin Kilbane were among the 5,000 interested spectators in Tallaght as the champions maintained their own unbeaten run.
Stephen Kenny made six changes to the side taken to penalties by Cliftonville in the Setanta Sports Cup, while Shels stuck with the same team that beat Derry City last week.
Spectators may have had to wait ten minutes for the game to start because of crowd congestion, but there was little delay in the drama once the whistle went.
Greene's ball caught out the Shels defence inside four minutes and Delany halted Dennehy's run on goal by tripping the winger.
Referee Derek Tomney produced a red card and Twigg compounded the visitors' misery by smashing the penalty past substitute Paul Skinner.
Shels, who impressed with ten men in the FAI Cup final, were forced to reorganise after Delany's dismissal, with winger Brendan McGill making way for Skinner.
Philly Hughes soldiered alone up front and drilled a free-kick narrowly wide of Oscar Jansson's right post as the visitors put up a fight.
It did not last long and Rovers enjoyed more of the ball with the extra man. Brennan and Chris Turner combined to create space for Dennehy. Skinner looked uneasy as he turned the shot wide.
The lead was doubled on the half hour in bizarre circumstances. Hurley was unaware of Skinner's position outside the box and played a blind pass that rolled into net.
Things got worse for Shels as Finn cracked in a long-range strike on 45 minutes. The midfielder was not closed down and Skinner could only get his fingertips to the ball as it flew in.
It was almost four soon after the break as a combination of the post, Lorcan Fitzgerald and Andy Boyle denied Twigg and Finn in a goalmouth scramble.
Shels rallied briefly and Jansson made a smart save to deny Paddy Kavanagh a goal on his return.
Greene punished poor defending from Ian Ryan for the fourth goal and made it a miserable night for Shelbourne fans. Those who wanted to leave early were unable to make a quick getaway as they were ordered to stay behind by Gardaí.
The Rovers fans that were allowed to leave early missed the late drama as McCabe was sent off 20 minutes after coming on.
Shamrock Rovers: 1 Oscar Jansson, 19 Sean Gannon, 4 Craig Sives, 5 Ken Oman (17 Graham Gartland h/t), 14 Killian Brennan; 6 Stephen Rice, 18 Chris Turner, 21 Ronan Finn, 20 Billy Dennehy (7 Gary McCabe '63), 14 Aaron Greene, 9 Gary Twigg 16 Daryl Kavanagh '75).
Subs: 30 Lee Steacy, 10 Gary O'Neill, 22 Conor McCormack, 23 Colin Hawkins.
Booked: Oman, Rice, McCabe. Sent-off: McCabe.
Shelbourne: 1 Dean Delany; 2 Gareth Matthews, 4 Andy Boyle (5 Stephen Paisley '81), 23 Ian Ryan, 3 Lorcan Fitzgerald; 11 Brendan McGill (13 Paul Skinner '6), 16 Stephen Hurley, 6 Glenn Cronin, 7 Conan Byrne (24 Anto Murphy '63); 14 Paddy Kavanagh; 9 Philip Hughes.
Subs: 6 David Cassidy, 12 Brian Shorthall, 17 Sean Byrne, 19 Philip Gorman.
Booked: Cronin. Sent-off: Delany.
Referee: D Tomney.