A 70th minute goal by Shelbourne striker Philip Hughes earned the Dublin side a second Premier Division win of the season over Derry City.
Hughes, who scored the winner when the sides clashed at Tolka Park in March, netted the only goal again in the 70th minute of Friday's Brandywell game.
Keeper Gerard Doherty got a touch on the first effort from Hughes who followed up to net into an open goal.
Earlier Doherty had made two fine saves to keep Derry on level terms.
The Candystripes keeper pulled off a tremendous one-handed save to turn the ball over when Anto Murphy's 25-yard shot appeared destined for the top corner in the 56th minute.
He then did equally well to deny Shels skipper David Cassidy whose well-struck shot came through a crowd of players on the area.
Rory Patterson almost got in for Derry but defender Stephen Paisley managed to block at the expense of a corner.
Near the end, substitute David McDaid shot into the side-netting with his first touch.
So Derry, who had been looking to make it four league wins in a row, fall to a third home defeat of the season.
City had already lost to Dundalk and St Pat's at their Brandywell base and this latest reverse will be a huge disappointment to boss Declan Devine, particularly as the league now goes into its three-week mid-season break.
Devine's men are next in action away to Cork on 22 June.