Shaun Miller grabbed the only goal of the game as Crewe Alex picked up their first victory since January 1 at Gresty Road on Saturday.
The on-loan striker popped up on the hour mark to blast in the clincher against in-form Colchester United.
It was an unattractive but effective display from the Railwaymen as they ended a run of six games without a success.
It has lifted them to 20th in League Two, six points above the drop zone.
Colchester United's League Two play-off hopes were dealt a blow this afternoon after they lost 1-0 at struggling Crewe Alexandra.
Shaun Miller's goal on the hour mark gave Alex all three points at Gresty Road and inflicted on the U's a disappointing defeat, their first in six matches in League Two.
Colchester, who remain three points off the play-off places, struggled to create many clearcut opportunities throughout the 90 minutes.
And although Crewe, who had gone into the game three points above the relegation zone and without a win in six matches, did not look particularly dangerous themselves they grabbed the all-important winner.
Colchester United Official Website
Colchester United have been beaten by a solitary goal at Crewe Alexandra.
The first half came and went without too much goalmouth action, with long range efforts from the U's failing to really test the home keeper.
After the break, a deflected free-kick fell to Shaun Miller, and he volleyed home to give Crewe a much needed win in their battle for survival.
Despite the U's bringing on three attacking substitutes, the hosts protected Ben Garratt and prevented the U's getting a late equaliser.