Dundalk bounced back from their first league defeat of the season to take all three points in an even contest at the Showgrounds.
Richie Towell claimed the winner from the penalty spot early in the second half, as the visitors came from behind to preserve their three-point lead at the top of the table.
A cracking first half saw Morten Nielsen grab his first league goal of the season, as the home side deservedly went in front on nine minutes. The Danish striker, playing in a wide right role, cut inside before firing a shot from outside the area that flew into the corner of the net.
There was little Rovers 'keeper Richard Brush could do to stop the leveller on 34 minutes as Horgan's superb cross was turned into his own net by Danny Ledwith under pressure from John Mountney. Dundalk grew in confidence and they edged in front 10 minutes into the second half.
The goal came after referee Paul McLaughlin adjudged that Alan Keane had handled Dane Massey's cross from the left. Towell stepped up to send Brush the wrong way from the spot for what proved the decisive goal.
Sligo Rovers 1 Dundalk2
Sligo - Brush, Keane, Peers, Folan, Ledwith, Cawley, Armstrong, Puri, Wearen (Ward 67), Nielsen (Devaney ht), Corcoran (Cretaro 61).
Dundalk - Rogers, Gannon, Boyle, Gartland, Massey, Mountney (Meenan ht), Towell, Shields, Horgan, Finn (O'Donnell 72), McMillan (Byrne 75).
Ref - P McLaughlin.