United's U21s saw their impressive 17 match unbeaten run in the Professional Development League come to an end at the Look Local Stadium on Monday afternoon.
The sequence which dates back to the beginning of November was ended by Femi Akinwande, who netted a goal in each half for the U's, who produced a very professional performance at the home of Stocksbridge Park Steels.
The visitors were quickly on the offensive and after Eastwood had stood tall to an effort at his near post, Brooks was needed to head off the line from the resulting corner.
The Blades were struggling to get a foothold in the contest and just after the half hour fell behind, as AKINWANDE fired home into the top corner on the angle.
Before the break, Colchester almost doubled their advantage, but a shot trickled inches wide of Eastwood's far post, with the goalkeeper scrambling across his line.
United made a change at the interval with De Girolamo replacing Kimarni Smith and the Italian youth international almost restored parity with a curling left-footed effort having engineered an opening for himself.
As the heavens opened, United's unbeaten record was in seriously jeopardy as AKINWANDE applied the finishing touch from much closer range after the Blades failed to their lines.
With the game petering out, De Girolamo came close for a second time, hitting the post, whilst at the other end Eastwood saved smartly, but in the end United's youngsters were forced to taste defeat for the first time since doing so at leaders Huddersfield Town on the 2nd November.
Speaking after the game, Coach John Dungworth was in reflective mood, but praised the youngsters for they had achieved in recent months and went on to demand a strong end to the campaign in the remaining three matches.
He said: "It is disappointing that such a fine run has come to an end, but ultimately it was just one of those days.
"We weren't at our best, we didn't start well and credit to Colchester they imposed themselves on the game and saw it out very well in the second-half.
"But the run is something for everyone to be proud of, especially the players, who deserve all the credit.
"Now we have to move on and make sure we finish well as we look to cement a top two finish and a place in the end season play-offs."
Blades: Eastwood, Charlesworth, Kelly, Gilmour, Banton, Semple, Coustrain (T. Smith 66) Brooks, Cockerline (Hall 74), Hallam, K. Smith (De Girolamo 45).
Unused: Ramsdale, Cummings.