Colchester manager John Ward admitted that his side never recovered against Sheffield United after conceding two early goals.
United were 2-0 down inside 12 minutes at Bramall Lane and went on to lose 3-0, with the final goal coming midway through the second half.
"It was a shocking start," said Ward. "Our defending in that first 10 minutes or so was very poor. At quarter past three, we were 2-0 down to a side I expect to be right up there at the end of the season and it was an uphill battle for us.
"I thought we might put them under a bit of pressure if we scored but we were unable to get a goal back. They were better than us and deserved the win.
"We'll always find it difficult to compete against clubs like this over the course of a season because there's quite a gap between the two clubs. I wanted to get a bit closer to them.
"Danny Wilson and Frank Barlow are extremely good at what they do and they've got some very good players to work with. I expect Sheffield United to be firmly in contention for promotion."