Veteran striker Andy Rammell hit a brace of goals, one in each half, to boost Rovers hopes of League survival.
Rammell’s first came on 29 minutes when he chased down Keeper Scott Howie’s goal-kick, flicking the ball past the advancing Shaun Marshall in the U’s goal.
The marksman grabbed his second on 65 minutes, firing past Marshall after latching onto Chris Llewellyn’s centre.
14 minutes later Vitalijs Astafjevs rapped up the win with a measured shot from the right after Graham Hyde and Llewellyn had made the opening for him.
Cambridge grabbed a late consolation with David Kitson converting a penalty with the last kick of the match.
The U’s had gone close to opening the scoring in the 18th minute when Daniel Chillingworth flashed in a wicked volley which Howie somehow managed to push away for a corner.
However, Rovers began to apply pressure to the U’s goal, forcing nine corners in the first 45 minutes.
And Marshall had to be at his best to keep Rovers lead down to a single goal in the opening half when he produced a first-class stop to deny Llewellyn.
Delighted Rovers manager Ray Graydon said: "The crowd were magnificent. This was our best performance for weeks and weeks. Everyone was lifted by the support flowing from the terraces and now we have to go on winning."