Shelbourne 2 (Cahill 43, J Byrne 95, Rodgers s/o 35)
Sligo Rovers 3 (Keogh 15, Gaffney 32, Feeney 105, McNamara s/o 95)
-----------------------
Tolka Park hasn't seen this much excitement since Sven Goran Eriksson decided to show his wrinkled mug at the Dublin Tournament at the start of the month.
Pat Fenlon's Premier Division leaders began the brighter and added a sense of deja-vous to the occasion when striker Jason Byrne struck the Sligo crossbar after seven minutes just as he had done in the Showgrounds last Sunday.
However Don O'Riordan's young westerners settled down and were soon a goal in front. Former Galway United midfielder Ollie Keogh hit a stunning, rising shot from all of 40 yards which caught out goalkeeper Steve Williams and looped under Shels' crossbar for the lead on 15 minutes.
A recent transfer to the Sligo club, Keogh had a hand in their second goal on 32 minutes as his corner was headed away by home defender Kevin Doherty only for teenager John Gaffney to redirect the rebound into the net from all of 25 yards.
Matters looked to have gone further into Sligo's favour when Dave Rogers was dismissed just two minutes later for dissent and a second yellow. Manager Fenlon booted the dugout in frustration as hopes of a revival seemed distant.
Most importantly Ollie Cahill brough them a goal back just before the break with a low 20-yard shot.
Shels looked as if they were on their way out as the match went into second half injury time, but striker Jason Byrne had other ideas and he levelled matters at 2-2 with a 95th minute free kick after defender Michael McNamara had hauled down the former Bray Wanderers' favourite when through on goal.
Chances went abegging from susbtitute Ger McCarthy, on for the ineffective Stephen Geogeghan, and midfielder Cahill before Feeney rose highest to head home Ian Rossiter's free kick nearing half time in extra time's first period, past a stranded Steve Williams.
Sligo held out for a famous win with Ramuel Miller dropping back into defence and shoring up for what was Shelbourne's third defeat of the season. Sligo meet Galway United in September's last eight, with last year's finalists Derry City and Shamrock Rovers plus the current league leaders all out of contention. Perhaps the Dublin ascendancy is faltering with currently three non-Dublin based sides in the top five of the Premier Division and six out of the eight clubs left in the FAI Cup play their football outside of the capital.
ATOGB Man-of-the-match: Paul McTiernan (Sligo) - Returning to the side and offered an outlet for Rovers when under pressure.
Shelbourne: Williams; Heary, Doherty, Rogers, Crawley; R Baker, Crawford, Morgan, Cahill; Byrne, Geoghegan.
Subs: Hoolahan for R Baker (60 mins), McCarthy for Geoghegan (71 mins), D Baker for Morgan (113 mins)
Sligo Rovers: Kelly; Rossiter, O'Dwyer, McNamara, Miller; Keogh, Gaffney, Feeney, O'Brien; Cretaro, McTiernan.
Subs: Purcell for Keogh (90 mins), Quinn for Gaffney (105 mins), Gorman for O'Brien (97 mins)
Referee: D McKeon (Dublin).