It was Jevons who had the best chance of the first half, having a header tipped over.
10 minuets after half time Dean Keates was denied a penalty, then Jevons shot just wide after Cambridge 'keeper Marshall fumbled a Shaun Smith shot. A City goal looked soon in coming.
The breakthrough came in the 70th minute when Justin Whittle powered a header in to get only his third ever goal for the club.
That was followed by a Shaun Smith free kick 3 minutes later that left Marshall with no chance to make it 2-0.
City line-up (4-4-2): Glennon; Regan, Whittle, Anderson, Smith; Johnson (Peat 65), Ashbee, Keates, Williams; Alexander, Jevons (Edwards 83).
Un-used subs: Musselwhite, Philpott, Bradshaw.