Home supporters greeted the final whistle with a chorus of boos and chants of "What a load of rubbish".
They weren't far wrong. Even the boost of a 24th minute penalty, converted by Junior Agogo after a foul by Simon Rae on Craig Disley failed to inspire Ian Atkins' team.
Two minutes later John Turner's measured cross from the left was met by Tudor who confidently beat Ryan Clarke from eight yards.
It took a brilliant Clarke save from Danny Webb's 57th minute header to keep Rovers on level terms as they constantly gave the ball away.
With winger Tudor in good form, Cambridge were always a threat going forward and might have scored twice before falling behind.
Turner was twice left with only Clarke to beat, having his first shot saved and seeing the second go narrowly wide.
Agogo went close for Rovers on a couple of occasions. But apart from his penalty the only other shot on target saw Cambridge keeper John Ruddy fingertip his late shot for a corner.
Cambridge boss Steve Thompson had good reason to suggest his side deserved all three points.
They were neater in their approach play and with better finishing would have recorded a morale boosting victory.
A blustery wind made life difficult for both sides and the defending early on boarded on the kamikaze.
Mistakes by Steve Elliott and Robbie Ryan offered Turner his chances, while at the other end the Cambridge backline looked little more secure.
Rae complained that he was hard done by when conceding the penalty, but he had a chance to clear before catching Disley, whose early runs from midfield proved a problem.
A collision between referee Tony Bates and Rovers midfielder James Hunt resulted in neither appearing for the second half.
Hunt was replaced by substitute Stuart Campbell while senior linesman Steve Bratt took over from Bates.