A fourth goal in five matches from Freddie Sears gave Colchester victory against 10-man Preston, who continue to struggle in League One.
The former West Ham youngster netted early in the second half after Jabo Ibehre had combined with George Porter.
Winger Lee Holmes came closest to an Preston equaliser, rattling the bar with a curling shot.
And North End's misery was complete when Bailey Wright was dismissed after an off-the-ball incident with Ibehre.
VIEWS FROM THE DRESSING ROOM
Colchester United manager Joe Dunne told BBC Essex:
"There are many types of victory, I suppose the three points counts at the end of the day, but I thought the manner of our victory was very, very pleasing.
"It was a gritty game, discipline was key. I thought we had enough quality, in terms of how we attacked Preston, to win the game.
"Preston threw everything at us, we defended exceptionally well, we knew what was coming.
"The first goal has been key in most of the games we've been involved in lately and when we got the first goal, you saw the confidence exude."
Preston manager Graham Westley told BBC Radio Lancashire:
"We're disappointed to have lost another game.
"The work ethic of the players was solid and the desire they were showing was clear and evident.
"The difference between what we're doing and winning is very slight, but we're stopping on the wrong side of the line on a consistent basis at the moment.
"We've got to make sure we change our mindset and get over the line."