Slough came into the game hoping to improve on a slow start to the season, and the visit of Cirencester, sitting joint top of the league, was anticipated to be a big test for the Rebels.
The Rebels were boosted by the return of skipper Gary MacDonald, as well as Nathan Webb and Eddie Smith, who limped off at Chesham on Bank Holiday Monday.
Slough had the better of the play overall in the first half, with Cirencester guilty of conceding possession easily.
Luke Williams saved from Zak Kotwica on 10 minutes, and at the other end Glyn Garner palmed over an effort from Webb.
The Rebels had good spells of pressure in the Cirencester half, but did not test Garner very often. The main threat from the home side came from Webb's set-pieces, but Slough were unable to make any of them count.
Four minutes from the interval, Williams was alert to turn away a shot from Josh Parsons as the visitors ended strongly.
The game needed something special to bring it to life, and two minutes into the second half, Charlie Mpi provided it. After working extremely hard to charge down a clearance on the touchline, Mpi capitalised on the loose ball and superbly lofted the ball over Garner from 25 yards to open the scoring.
Three minutes later, Slough worked the ball out wide to Warren Harris, whose deflected shot was somehow cleared off the line by the knee of defender Ben Brown.
Slough continued to play with confidence, closing down their opponents swiftly and denying them any kind of space to play.
Eddie Smith curled a shot over and on 69 minutes was denied by Garner after being released by Mpi, the keeper deflecting the ball behind for a corner.
With chances still at a premium, Williams made a comfortable save from Parsons' long-range shot, and Aiden Bennett hit a speculative effort wide from distance.
On 77 minutes, centre back Leigh Henry put the ball wide at the far post from a free kick as Cirencester struggled to create openings against a far more solid-looking Slough.
There was to be one final scare as the visitors had a shot blocked in a crowded goalmouth in stoppage time, but the Rebels deservedly held on to their single goal advantage and claimed the points with a superb team performance.
Cirencester Town Line up
Glyn Garner, Gethin Jones, Ian Herring, Ben Brown, Brad Hooper, Leigh Henry (c), Ross Langworthy, James Mortimer-Jones, Charlie Griffin, Josh Parsons, Zak Kotwica. Subs: Aiden Bennett, Mark Pritchett, Olly Knight, Sam Farr.