With the hosts’ season in danger of petering out into mid-table anonymity, it was imperative they made a bright start but they were stunned inside the opening two minutes as the visitors grabbed the lead.
After Chris Bennion had dealt unconvincingly with a Ross Gaynor free-kick, the resultant corner from Gaynor was met by Jason McGuinness, who rose unopposed to flick to the net from six yards.
The visitors, who garnered a crucial point in Tallaght on Monday evening, were happy to sit tight and allow Shelbourne a degree of possession but they were never troubled despite some sporadic raids by the lively Kevin Dawson.
Sligo doubled their lead in the 16th minute. Gaynor was once again the provider from a free-kick and with Shelbourne leaving acres behind them, McGuinness’ central defensive partner Gavin Peers sidefooted home from 12 yards with Bennion equally culpable as he allowed the shot to squirm under his body.
The procession towards the Drumcondra End continued unabated with Gaynor continuing to wreak havoc and on the half-hour, another precise delivery found the head of Seamus Conneely who headed over from six yards under pressure from Lorcan Fitzgerald.
A surging break by Sean Byrne that culminated in a 20-yard shot that failed to unduly trouble Gary Rogers in the 41st minute was the height of Shelbourne’s attacking intent.
On the hour mark, Alan Keane escaped down the right flank and his inviting cross eventually fell to David Cawley, whose volleyed attempt from 10 yards was parried to safety by a badly exposed Bennion.
Chances ensued for both Mark Quigley and Millien as the half progressed, before the former effectively settled the contest in the 77th minute when calmly converting from the penalty spot after Shortall’s clumsy challenge on substitute Liam Buchanan.
Within six minutes, a consolation goal arrived for the hosts with Paddy Kavanagh make an immediate impact upon his introduction as he struck a sublime cross-shot beyond the despairing dive of Rogers from 20 yards.
SHELBOURNE: Bennion; Matthews, Boyle, Shortall, Fitzgerald; Hurley (Gorman, 56), Cronin, Cassidy (Kavanagh, 80), Dawson, Byrne (Clancy, 70); Hughes.
SLIGO ROVERS: Rogers; Keane, Peers, McGuinness, Gaynor; Conneely (Lynch, 79), Cawley, Ventre (Buchanan, 69), Boco; Quigley, Millien.
Referee: Paul Tuite (Dublin)