Cheltenham loanee Owusu struck on 57 minutes when he rose high to nod home a precise free-kick from left-back Gary Borrowdale.
It was a lead that the Sussex visitors rarely looked like relinquishing. In fact, they could have added to their tally because they bossed the whole of the second half against a desperately disappointing Colchester team.
Brighton are now just three points away from clambering out of the relegation zone, and they also have a game in hand, so there is genuine hope of survival for Russell Slade's men.
Colchester had shaded the first half despite being below-par, but they could not find an early goal and then drifted out of the game completely after the break.
Manager Paul Lambert had made five changes to the side that had lost at Leyton Orient, yet they failed to liven up the team, despite half-chances for Mark Yeates and Ashley Vincent in the first period.
On both occasions, keeper Michels Kuipers saved well, parrying Yeates' close-range shot and then comfortably smothering a long-range drive from Vincent.
But it was Brighton that stepped up a gear and took control, especially after Owusu had broken the deadlock.
Star man Dean Cox thought that he should have won a penalty when he seemed to be upended by John White, while on 86 minutes substitute Calvin Andrew was clean through on goal, only to be thwarted by a good block by home keeper Dean Gerken.
Earlier defender Pat Baldwin had also come to Colchester's rescue with a last-ditch challenge from Gary Hart, just as the Brighton striker was poised to sweep home the loose ball after Gerken had charged down Cox's initial shot.