SHEFFIELD United had to settle for a point from their first visit to the Weston Homes Community Stadium.
Steven Gillespie’s superb strike cancelled out Will Hoskins’s first-half opener for Blades in a keenly-contested affair in Essex.
The point means Danny Wilson’s team now lead city rivals Wednesday by just two points, with the Steel City clubs having played the same number of games.
Blades goalkeeper Steve Simonsen denied Ian Henderson’s low, close-range effort early on and Anthony Wordsworth went close for the home side with an acrobatic effort.
But Sheffield United were the better side in the first half and after Stephen Quinn’s deflected effort flew over, the visitors took the lead just after the half hour.
Former Rotherham United striker Hoskins coolly lifted the ball over U’s goalkeeper Ben Williams from close range after Ched Evans had picked him out in space from the edge of the area.
But Colchester were back on level terms 11 minutes after half-time through Gillespie, who curled a superb shot into the far top corner from just outside the area after Kayode Odejayi had laid the ball off.
Gillespie went close twice more after that leading to a heated disagreement between Blades team-mates Matthew Lowton and Lee Williamson.
Blades top scorer Evans’s powerful run and shot forced U’s goalkeeper Williams to push the ball away for a corner with 20 minutes to go then at the other end Henderson forced Simonsen into action with a low, long-range effort.
Both sides went for a winner in the closing stages but the match finished all square.
Colchester United: Williams, Wilson, Okuonghae, Eastman, White, Izzet, Bond, Wordsworth, Henderson (sub Duguid, 89), Gillespie, Odejayi. Unused substitutes: Rose, Heath, Vincent, Sears.
Sheffield United: Simonsen, Lowton, Hill, Doyle, Maguire, Williams, Williamson, Quinn, Hoskins (sub Creswell, 71), Porter (sub Beattie, 81), Evans. Unused substitutes: Montgomery, Howard, Egan.
Referee: T Kettle (Rutland).
Liverpool captain Steven Gerrard hit a memorable hat-trick to sink Everton 3-0 in the 217th Merseyside derby.
The Reds’ inspiration, back in the starting line-up after injury, completed his treble in stoppage time as Kenny Dalglish’s men ended a run of three successive Barclays Premier League defeats.
Fixtures (7.45 unless stated)
UEFA Champions League First Knock-Out Round Second Leg: Chelsea v Napoli, Real Madrid v CSKA Moscow.
Central League Division One Central: Burton Albion v Port Vale (7.00), Sheff Utd v Nottm Forest (1.00).
Division One East: Hartlepool v Middlesbrough (7.00).