Johnnie Jackson's equaliser against 10-man Cardiff ended Colchester's sorry run of five straight defeats.
All seemed routine when Paul Parry's strike, his ninth of the season, gave Cardiff the lead but Colchester should have claimed the three points.
Clive Platt hit the post and then Jimmy Floyd Hasselbaink was sent off for a challenge on goalkeeper Dean Gerken.
They finally scored when Jackson hit home a Karl Duguid corner, while Medy Elito came close to scoring the winner.
Colchester boss Geraint Williams:
"The effort is always there, but we played some good football and I felt that we created good openings.
"I was delighted with the performance and, from the first minute until the last, I thought we were magnificent."
Cardiff boss Dave Jones on Hasselbaink's red card:
"I hope the FA will look at it and go from there because to have him suspended would be a killer for us.
"Colchester are fighting for their lives - you could see that from the word go. They were effective."
Colchester: Gerken, Ifil, Heath, Virgo, White (Vernon 84), Duguid, Hammond, Jackson, Elito (Wordsworth 87), Lisbie, Platt.
Subs Not Used: Bankole, Balogh, Izzet.
Goals: Jackson 71.
Cardiff: Enckelman, Blake, Johnson, Loovens, Capaldi, Whittingham (Sinclair 66), Rae, Ramsey (Scimeca 77), Ledley (Thompson 78), Hasselbaink, Parry.
Subs Not Used: Oakes, Purse.
Sent Off: Hasselbaink (62).
Booked: Blake.
Goals: Parry 11.
Att: 4,699
Ref: Kevin Wright (Cambridgeshire).
~RS~q~RS~~RS~z~RS~07~RS~)