Ray Jones scored his sixth goal of the season to get Rangers back to winning ways following two defeats over Christmas.
Colchester may be flying at home after 11 straight wins, but they looked out of sorts again on the road in this their tenth game in 11 without a win away from Layer Road.
Lee Cook was the star of the show for the home side with Premiership clubs taking a keen interest. His darting runs terrorised defenders throughout.
Rangers' young strike partnership of Dexter Blackstock and Jones were also causing Colchester centre-backs Pat Baldwin and Wayne Brown all sorts of trouble with their aerial presence.
And with Cook on his finest from on the left-hand side, it was a frightening combination - and it led to the only goal of the game on 36 minutes.
A superb cross from the 24-year-old was met by Jones with a looping header into the far corner, giving goalkeeper Dean Gerken little chance.
The high-flying U's had barely turned up at this point - and it gave them the kick-start they needed.
Rangers were given a stark warning of what Geraint Williams' side are capable of on the stroke of half-time when Kevin McLeod put in a perfect ball which rolled right across the face of goal.
Jamie Cureton and Richard Garcia were both on hand for a tap-in, but somehow neither of them could connect with the ball, and the chance went begging.
But Rangers were soon back on the offensive as soon as the second half kicked off. Colchester's defence failed to deal with a clearance and, after one bounce, Kevin Gallen hit a volley which Gerken spectacularly tipped onto the bar.
The chances were coming thick and fast as Blackstock next found himself in the clear after a defensive error, but took too much time over his finish as the keeper closed him down.
Cook was also back at his best on 57 minutes when another cross picked out the unmarked Jones - but he was less accurate with his header this time and skied it.
Colchester struggled to get their familiar passing game together and their best chance of the half came when substitute Johnnie Jackson headed just wide 13 minutes from time.