The Brandywell game was the first in the League of Ireland for 146 days but unfortunately City failed to live up to the occasion.
The match was played behind closed doors without fans because of the Coronavirus pandemic.
Ryan McFadden headed in from a corner to put Sligo ahead on 19 minutes and Ronan Coughlan’s penalty double the lead five minutes into the second half.
The hosts rarely threatened although Gerardo Bruna wasted a good chance.
The 2-0 victory secured the visitors first victory of the season with an impressive win on the road.
As for Declan Devine’s players, they struggled throughout and never tested Rovers goalkeeper Ed McGinty during the 90 minutes.
With the game being played behind closed doors, the Candystripes had fake crowd noise pumped out through the PA system in the Brandywell Stadium.
But it didn’t help Derry’s performance.
The visitors took the lead on 19 minutes after Regan Donelon’s right-wing corner found centre-back Callan-McFadden, and the big centre-back rose unchallenged to head home from close range.
Rovers would have added a second minutes later as the dangerous Coughlan found himself some space inside the Derry box, but his low drive was superbly blocked by a diving Eoin Toal.
Derry went close to levelling things on 40 minutes, but Conor McCormack’s close-range strike was deflected wide.
Just before the break, Rovers felt they should have had a penalty, but referee David McLaughlin waved away their protests after Coughlan seemed to be upended by McCormack.
The Bit O’Red were awarded a penalty on 51 minutes after Coughlan, who was a handful all game, was brought down inside the box by Toal. The striker stepped up and side-footed home the resulting spot-kick.
McGinty nearly gifted Derry a way back into the contest on 70 minutes when he raced out to the edge of his area, but fortunately for the keeper Gerardo Bruna’s attempted lob into the unguarded net flew well over.
In the 90th minute, Figueira, who struggled for long parts, went close to grabbing a consolation goal.
However, his shot sailed just past McGinty’s right-hand post.
Next up for the Candystripes is an away match at Richmond Park when they face St Pat’s (kick off 7.45 pm).
Derry City: Peter Cherrie, Conor McCormack, Eoin Toal, Ally Gilchrist (Mark McChrystal HT), Ciaran Coll; Conor Clifford (Jack Malone 58), Gerardo Bruna, Joe Thomson; Ciaron Harkin (Patrick Ferry 58), Walter Figueira, Stephen Mallon.
Sligo Rovers: Ed McGinty, Darragh Noone, Kyle McFadden, Garry Buckey (John Russell 73), Regan Donelon; Will Seymore, David Cawley, Niall Morahan; Jesse Devers (Darron Collins 80), Ryan Coughlan, Ryan De Vries.Referee: Paul McLaughlin (Monaghan).