Geraint Williams lamented his side's sluggish start, after seeing them slide to a 2-1 defeat at Stoke City.
The U's found themselves behind after only eight minutes at the Britannia Stadium, after Ryan Shawcross headed the Potters ahead from Liam Lawrence's corner.
And although Clive Platt equalised, Lawrence fired in Stoke's winner with 17 minutes to go, leaving Williams to highlight Colchester's poor opening as their main downfall.
He said: "I don't like losing at anytime. I hate losing but I don't shout and moan about it.
"I've got a lovely bunch of lads in the dressing room but they've got to start games on the front foot.
"We have to be more aggressive, not in a nasty way but in terms of matching teams early on.
"We're frustrated and disappointed. We knew the challenge coming to Stoke. They're a big side and we spoke about the early battles but we conceded from a set piece.
"I was disappointed with the fact that we had to come back again and that's something we have to learn."
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