David Wright volleyed a difficult chance onto the roof of the net, following Sanchez Watt’s deep cross to the far post.
But the biggest flashpoint of the half came ten minutes before the break when Watt tucked the ball into the vacant net, only for referee Brendan Malone to rule the effort out for a foul on Rotherham keeper Adam Collin.
It proved to be one of Malone’s meaningful last acts in the middle, as he departed minutes later with the earlier injury he had sustained and was replaced by fourth official, Essex’s Fred Graham.
Graham waved away Rotherham’s penalty appeals in the fourth minute of stoppage-time when Colchester defender Magnus Okuonghae appeared to shove Kieran Agard inside the area, prior to an even first half coming to an end.
Agard spectacularly volleyed over from Lee Frecklington’s cross in the minutes that immediately followed half-time and Haris Vuckic fired straight at U’s keeper Sam Walker, as the visitors warmed to the task.
Walker plucked Agard’s looping effort out of the air as it was heading towards the top corner and the U’s shot-stopper then made an ever better save minutes later to stop former Braintree Town striker Alex Revell’s low shot.
But midway through the second half, Watt was desperately unlucky to see his close-range shot crash against the crossbar, following Wright’s ball into the area.
Rotherham substitute Nicky Adams volleyed a good chance over from close range with 12 minutes to go but as the clock ticked down, the play ebbed and flowed and either side might have claimed the points but in the end, the spoils were shared.
For a full report and pictures, see Wednesday's Gazette.