Nuneaton 2-2 Cambridge
James Jennings snatched a last-minute equaliser for Cambridge at Nuneaton.
Tom Elliott fired the visitors ahead after the break, but Adam Walker's precise finish pegged them back.
Cambridge's Robbie Willmott saw a penalty saved late on, before U's keeper Jonathan Hedge saw red for bringing down Wesley York.
Striker Liam Hughes went in goal and could not keep out the resulting penalty from James Armson, but Jennings levelled with a last-gasp free-kick.
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Cambridge United manager Jez George told BBC Radio Cambridgeshire:
"Self-inflicted drama and I am fuming. It was really unprofessional, when you come to a place like this you know they are going to work hard.
"To gift them an equaliser a few seconds after scoring a goal is unprofessional and unacceptable.
"It was so important to get that first goal and then we go and throw the advantage away. I'm unhappy about a lot of our performance today. We have to impose ourselves better on opponents than we are doing at the moment and we've come unstuck today."