Southend United's Barry Corr scored a second-half header to take all three points from Cambridge United on Boxing Day.
After a goalless first half, it was the visitors that were applying the pressure, as the Shrimpers bombarded the home side's goal early on.
It was Southend who started the second half the brighter and 15 minutes after the restart, Corr broke the deadlock with a headed goal which Cambridge keeper Chris Dunn was helpless to save.
The victory sees Southend go above Plymouth Argyle for the time being, as Plymouth play Newport County later on.
Defeat sees Cambridge drop down the table to 13th, four points off the playoff places.