The ten men of Finn Harps scored twice in the final five minutes of the game to earn them a point in their bid to avoid the relegation play-off spot.
Kosovar Sadiki saw red just five minutes into this encounter, with Johnny Kenny having a spot kick saved five minutes before the interval.
Kenny and Niall Morahan gave Sligo a decent cushion as the game approached the hour mark but goals from Sean Boyd and Karl O’Sullivan ensured Liam Buckley’s team left Donegal with only one point instead of three.
Both teams came into this encounter in a very similar run of form, with only one win in their last five league outings.
Sligo Rovers started on the front foot in the derby and Johnny Kenny forced Mark McGinley into a save less than two minutes in with a close range header.
Just a couple of minutes later, Finn Harps were reduced to ten men. Kosovar Sadiki caught Kenny in the middle of the park with a late tackle and the referee did not hesitate to reach for his back pocket.
Despite the numerical disadvantage, the hosts could have taken the lead with their very next venture forward. A mistake in the defence allowed Barry McNamee to slide through Tunde Owolabi and the in-form striker rounded Ed McGinty but saw his shot from an acute angle blocked on the line by Garry Buckley.
Harps fashioned another opportunity on the quarter hour with Shane McEleney playing through Owolabi on the counter but a poor first touch allowed Sligo to track back and thwart the chance.
Sligo enjoyed a strong spell beyond the half hour mark and only for McGinley, they could have been more than a goal up.
The shot-stopper first got a strong hand on a strike from distance by Adam McDonnell and he also got down well to palm away a low effort from Walter Figuiera.
With five minutes to go in the half, Sligo were awarded a spot kick after a foul in the area by Mark Coyle on Johnny Kenny. The fouled party stepped up and fired straight down the middle with McGinley saving the penalty with his feet as the sides went into the interval all square.
Less than 60 seconds into the second half and Sligo broke the deadlock with Kenny coolly slotting the ball beyond the onrushing McGinley from just inside the area.
Just under ten minutes later and Sligo had doubled their lead. Following a corner, Finn Harps failed to clear their lines properly and Niall Morahan lay in wait on the edge of the area to rifle an effort into the bottom left corner.
There was very little goalmouth action after Sligo Rovers doubled their lead as it looked like the side from the Showgrounds would coast towards the three points.
Harps, however, had different ideas and with only five minutes to go, Sean Boyd ensured a tense finale, heading home from close range after a corner from Dan Hawkins.
Harps put the pressure on Sligo in the dying embers of the game and in the last remaining seconds, they got their reward.
Ethan Boyle found Karl O’Sullivan in space in the area and the substitute finished from point blank range as Harps earned an unlikely point.
Finn Harps: Mark McGinley; Jordan Mustoe, Kosovar Sadiki, David Webster(Adam Foley 84), Shane McEleney; Ryan Connolly(Karl O’Sullivan 64), Mark Coyle, Ryan Rainey, Will Seymore(Ethan Boyle ht), Barry McNamee(Dan Hawkins 64); Tunde Owolabi(Sean Boyd 64).
Subs not used: Patrick McGarvey, Mark Timlin, Luke Rudden, Stephen Doherty.
Sent off: Kosovar Sadiki (5).
Sligo Rovers: Ed McGinty; Lewis Banks, Robbie McCourt, Adam McDonnell, John Mahon; Niall Morahan, Walter Figuiera (Melvyn Lorenzen 78), David Cawley, Johnny Kenny(Romeo Parkes 78); Ryan De Vries, Garry Buckley.
Subs not used: Richard Brush, Danny Kane, Seamus Keogh, Mark Byrne , Regan Donelon, Darren Collins, Andre Wright.
Booked: Lewis Banks (17) Niall Morahan (25).
Referee: Damien McGraith
ExtraTime.ie Player of the Match: Niall Morahan (Sligo Rovers)