The visitors ran out winners, with striker Adebayo Azeez netting the game's only goal with just under ten minutes remaining.
But the match served as an excellent exercise for several players whose game time has been limited recently, with captain Alan Sheehan and Lloyd Jones playing at centre-half, Dan Potts at left-back, Jack Senior in a midfield role - before reverting to right-back - with Danny Hylton and Aaron Jarvis up front.
Also in the midfield along with Thorne and Moncur, who both made impressive debuts as second-half substitutes in the 4-0 win over Peterborough on Saturday, was teenager Arthur Read.
Harry Isted was in goal, and the young keeper produced the moment of the first-half, diving to his right to keep out a penalty from Azeez after Sheehan had been penalised for a foul.
The Town had the better of the second half and almost took the lead when Moncur bent a low shot from the edge of the box that the U's keeper did well to tip around the post.
Moncur and Hylton both aimed efforts straight at the keeper, then Read saw a shot blocked before Josh Neufville - who started wide on the right, then went into a number ten role - fired into the side-netting.
Cambridge then nicked it with Azeez bursting into the left side of the penalty area and slipping a neat finish under Isted for the winner.
TOWN: Isted, Neufville, L Jones, Sheehan (c), Potts (Kalonda), Thorne (Beckwith), Read, Senior, Moncur (Richardson), Hylton, Jarvis. Subs: Parker, A Jones, Boorn, Byron.