Cambridge claimed a 2-1 win against Newport at a rain-soaked Abbey Stadium to move above their opponents and into second in Sky Bet League Two.
A key flashpoint came after 21 minutes when U's midfielder Luke Hannant kicked out at Joss Labadie but escaped punishment from referee Carl Brook.
Labadie fired a great chance over moments later, after which the home side enjoyed a dominant spell.
Harry Darling's header was disallowed for offside, and in the 33rd minute Paul Mullin rounded Nick Townsend before being denied by the recovering goalkeeper.
Seven minutes before half-time Mullin broke the deadlock, firing home Wes Hoolahan's cross after a good move down the left.
The start of the second half was delayed by 10 minutes while standing water was cleared from the pitch following a first-half downpour.
Mullin doubled his tally for the afternoon after 61 minutes, with Hoolahan again the provider, firing into the roof of the net after Newport had given the ball away.
Scott Twine halved the deficit with a stunning 30-yard effort six minutes later which flew in off the underside of the crossbar, but County could not find an equaliser.