The Reds, who were managed by Noel King and Alan Mathews on the night following Keely's decision to take a month out of football for health reasons, secured the victory through goals from Jim Crawford and Jim Gannon either side of half time.
Crawford opened the scoring on the stroke of the break. The former Newcastle United player produced a brilliant mazy run, before rounding Matt Gregg in the Bray goal.
Then with just nine minutes remaining on the clock, Jim Gannon, back after a ban, celebrated his return with a header from a Davy Byrne cross.
Derry City were held to a 1-1 draw by Longford Town at the Brandywell on Thursday night.
Gareth McGlynn gave the home side the lead a minute into injury time at the end of the first half. Tommy McCallion short free-kick found Liam Coyle, who put McGlynn through to send a weak shot past O'Brien in the Longford goal. However, Sean Prunty struck on 54 minutes to prevent City from joining Rovers at the top of the eircom league.
The Candystripes remain two points behind league leaders Shamrock Rovers with a game more played.
In Thursday night's other eircom league action, Paul Doolin's UCD moved above Bohemians and Cork City with a 1-0 victory over strugglers Monaghan United.
Clive Delaney scored the only goal of the game to make it five games without defeat for the Students.
eircom league premier division
UCD 1 (C Delaney 21, McDonnell s/o 90) Monaghan Utd 0
Shelbourne 2 (Crawford 45, Gannon 82) Bray Wanderers 0
Derry City 1 (McGlynn 45) Longford Town 1 (Prunty 52)
Click here for the premier division table