The Blades picked up a second successive away draw but will once again believe their efforts warranted more.
John Cofie gave the Blades a first half lead but a close-range effort from Clinton Morrison earned Colchester their third consecutive draw of the season.
It was also the second 1-1 draw between the Blades and Colchester at the Weston Homes Community Stadium in 2012 and once again the Blades had the majority of chances, although Andy Bond went close for the home side late on in Saturday's encounter.
Boss Wilson named an unchanged squad for the visit to Colchester United. The same starting XI and substitutes from Tuesday's draw at Coventry were on duty and, like at the Ricoh Arena, it was difficult to determine the formation that the Blades were operating, with Quinn particularly fluid in midfield early on.
A quick free-kick caught Colchester napping to give the 893 travelling Unitedites early hope and the home side's first attempt was a shot from Sears, from a central position, but Howard was untroubled.
On 14 minutes, from Maguire's ball down the right channel, Quinn got the better of O'Toole but his shot was saved by Cousins, low to his right, whilst from the resulting corner Maguire headed into the goalkeeper's arms. However, within minutes, the Blades were ahead.
Earlier in the move, COFIE had a shot block but Doyle picked up the loose ball and found the loan striker, who cut in from the left before unleashing a 30-yard piledriver that sailed over the head of Cousins, nestling in the back of the net.
The net that Cousins was defending was certainly the busier in the first half. McAllister headed onto the roof of the goal after Cofie had flicked on Hill's cross and on 33 minutes the magic of McDonald almost made the Blades a second goal. The Scottish midfielder danced into the box after a neat move on the left, rounding the goalkeeper but Cofie could not convert the pull-back.
With McDonald and Quinn prominent, the Blades were opening Colchester up regularly in the first half and Cousins had to be alert to cut out a couple of crosses, whilst he also saved a Quinn shot.
A goal advantage going into the second half, the visitors began well after the break. Former Blades loanee O'Toole was taken off on 47 minutes and soon after McMahon curled a free-kick into the sidenetting - Blackman then had a shot blocked by the goalkeeper's legs, whilst Hill and Quinn also had efforts which hit defenders.
Goalscorer Cofie was replaced by Miller just after the hour and a rare Colchester attack saw Morrison shoot wide, unable to lose the attentions of Maguire. But, after McMahon had driven wide for the Blades, Colchester levelled. From a corner, the delivery was initially won by Bean and MORRISON, positioned in front of Howard, managed to divert the ball slightly, beating the goalkeeper.
Morrison was blocked as he looked for another as the home side used the impetus but the Blades rallied and attempted to regained the upper hand. Quinn, booked for a foul on Bean in the second half, had a shot saved by Cousins, after good build up by McDonald and Blackman.
With five minutes left Colchester went very close to taking the lead. Bond found space on the right and his shot looked harmless but a deflection off Hill saw the ball strike the inside of a post and roll across the front of the goal.
Three minutes of added time saw Cousins flick a header from McMahon onto the crossbar from a Quinn free-kick. Blackman and Wordsworth were booked following a melee and Colchester survived a late corner before it was confirmed the points were shared.
Colchester: Cousins, Rose, Okuonghae, Heath, O'Toole (Bond 47), Morrison, Sears (Massey 88), Bean, Henderson, Wilson, Wordsworth.
Unused: Pentney, Duguid, Izzet, Eastman, White.
Blades: Howard, Maguire, Hill, Doyle, Blackman, McDonald, Collins, McAllister, Cofie (Miller 64), Quinn, McMahon.
Unused: Flynn, Harriott, Philliskirk, Ironside, Long, Williams.