Substitute Cian Kavanagh's header decided a massive game in the West, with a big crowd present to see Galway's struggles deepen and Sligo edge nearer to safety.
The visitors barely showed up in the first half but had enough quality to break the stalemate early in the second. Still, United will wonder how they did not equalise through Dara McGuinness, as their strikers' dire run in front of goal continued since Moses Dyer departed.
Sligo look to have enough about them to finish at least eighth, and Galway can look forward to bottom side Cork visiting Friday, a game both need to win.
Terryland was rocking long before kick-off in one of the most significant Connacht derbies this century, with an emotional round of applause for the late Ollie Horgan before the first game here since his tragic passing earlier this month.
Whilst yet to score, McGuinness has shown promise for United, and his pace is an asset which helped him win the ball on 19 minutes and play it to Jimmy Keohane, whose effort was easily collected by Sam Sergeant.
Cian Kavanagh with a massive goal to give Sligo Rovers the lead in the Connacht derby! pic.twitter.com/CMArdOD1PZ
— League of Ireland (@LeagueofIreland) September 22, 2025
Then big Gareth McElroy used his frame to block a drive from ex-Rovers defender Garry Buckley, with Rob Slevin's header cleared off the line from the subsequent corner – United desperate to score first against a Sligo team perhaps reeling from conceding four in the FAI Cup in Kerry.
Sligo offered little, lacking confidence; they have classy attacking players but failed to gain a foothold in a scrappy game involving two struggling sides.
This was summed up when one of the league's hottest prospects – Owen Elding – badly mis-controlled at the edge of the box ten minutes before the end of a poor first half.
Jad Hakiki, fresh from excelling for Ireland's Under-21s, looked to be in only for a fine Bobby Burns challenge. That, at least, suggested Sligo were sensing that Galway were vulnerable.
However, the strapping Patrick Hickey nearly put United ahead from Jeannot Esua's cross at the end of the half, but he lacked conviction in keeping with the tepid fare.
Sligo should have been in front seven minutes into the second half. Ryan O'Kane's cross presenting Hakiki with a sitter, but he completely missed the ball a few yards out.
It was clear that John Russell had been in the heads of his players at the interval and they were much better in the restart, Elding prompting a fine save from the in-form Clarke after a neat pass from O'Kane.
And, from that corner, Sligo went in front after 54 minutes.
From Will Fitzerald's corner, Brendan Clarke missed his intended punch and Kavanagh headed in after McElroy nodded in his direction.
Galway were now struggling, especially without the suspended David Hurley, and the impressive Offaly native Edwin Agbaje smashed a shot goal-bound that Hakiki nearly hooked in.
United rallied in what was already a cracking second half.
McGuinness raced down the left and squared the ball, only for Sergeant to parry; luckily for him, he had time to collect as no United player could get there in time.
United lacked creativity and, when they crossed the ball into the box – as they did with regularity in the second half – Rovers were able to get bodies about the danger.
Rovers' threat was clear at the other end, with Clarke forced to save from a nice drive from Hakiki outside the box.
Quite how McGuinness didn't score from about five yards out with eight minutes to go was staggering. He poked straight at Sergeant, whose parry just about went over the bar rather than under, when it seemed far simpler to score.
It was by a stretch the best chance United had. And their last.
Galway United: Brendan Clarke; Jeannot Esua, Killian Brouder (Vincent Borden 84), Garry Buckley, Bobby Burns; Aaron Bolger (Jeremy Sivi 64), Jimmy Keohane, Rob Slevin, Ed McCarthy (Stephen Walsh 64), Patrick Hickey; Dara McGuinness.
Sligo Rovers: Sam Sargeant; Edwin Agbaje, Patrick McClean, Gareth McElroy, Sean Stewart (Ciaron Harkin 63); James McManus (Matty Wolfe 63), Seb Quirk (Cian Kavanagh 46); Ryan O'Kane (Kyle McDonagh 83), Jad Hakiki, Will Fitzgerald; Owen Elding.
Referee: Paul Norton.
