Paul Cook's Sligo Rovers blew the Airtricity League Premier Division title race wide open with a blistering 2-0 victory over Shamrock Rovers at the Showgrounds last night.
Dubliner Gavin Peers headed home the crucial opening goal six minutes before the break as the Bit O'Red narrowed the gap to just two points on the reigning champions.
Sligo's win allowed the Hoops' Dublin rivals St Patrick's Athletic to take top spot after their victory over Bray.
Eoin Doyle secured the deserved points for the hosts, as he slid home the second goal in injury-time of an enthralling game.
It was the first time that the home side had beaten the visitors since last year's FAI Cup win at the Aviva Stadium, and it means the Hoops have now dropped five points in their two games this week.
In team news, Iarfhlaith Davoren missed out again for the hosts, who recalled the experienced Joseph Ndo and Alan Kirby.
Michael O'Neill was not pleased with his side's performance against Dundalk midweek and left Gary Twigg and Dan Murray on the bench.
Karl Sheppard also missed out through injury, which meant Gary O'Neill started as a lone striker.
Chris Turner started in midfield but lasted just 21 minutes before pulling up injured, prompting an early introduction for Ronan Finn.
Ken Oman was passed fit to start for the Hoops and was called into action early, blocking an Aaron Greene cross that threatened to pick out Matthew Blinkhorn in a dangerous position.
Billy Dennehy and Gary McCabe had half-chances for the visitors as they settled into the game, but both players also picked up early bookings, as did Conor McCormack, as the home side took the game to the league leaders.
They were rewarded on 39 minutes from another Ndo set-piece, as Peers found himself completely unmarked in the area to head past Alan Mannus.
And they threatened again before the break, but Richie Ryan's free-kick from a dangerous position was too high to trouble the Hoops netminder.
The intensity remained high into the second half.The home fans were screaming for a penalty on 53 minutes, when Blinkhorn picked out Alan Kirby, and he combined with Eoin Doyle to set up Raffaele Cretaro.
The former Bohs man stepped inside Enda Stevens and went to ground, but referee Anthony Buttimer opted to book Cretaro for simulation.
Greene then saw a cross-cum-shot from the left bounce off the top of the crossbar, before O'Neill reacted by springing Twigg from the bench.
Ciaran Kilduff was also introduced soon after as the Hoops went 4-4-2, and he had strong claims for a penalty turned down on his first involvement.
He took a pass from McCabe inside the area but found Peers in his way as he looked for a way through. The Hoops roared for obstruction, but Buttimer was again unimpressed.
Sligo substitute John Dillon and Doyle could have made life more comfortable for the hosts in the closing stages, had they not missed the target from good openings.
But Doyle finally wrapped it up in injury-time by latching onto Dillon's superb pass and taking the ball around Mannus before sliding it home.