The former Rovers striker capitalised on a mistake by Garry Kenneth six minutes before the break to fire home at the second attempt after his first effort was blocked.
Goalkeeper Neil Etheridge had come to Rovers' rescue with a brave save at the feet of Kaid Mohamed on 22 minutes as the home side found themselves second to the ball in the first half.
Etheridge, on loan from Fulham, kept Rovers in the game after the break with further brilliant saves from Jermaine McGlashan, Billy Jones and Mohamed.
Robins keeper Scott Brown did well to keep out two David Clarkson shots and the visitors had to absorb some late pressure, but were good value for all three points.
Rovers have yet to win at home this season and took far too long to hit top gear, so it was no surprise to hear their long-suffering fans greet the final whistle with boos.