FC Halifax Town 1-1 Cambridge United
Cambridge were frustrated in their bid to cut Luton's lead at top of the Conference Premier after being held by 10-man Halifax.
Tom Elliot headed home from Harrison Dunk's cross just after the hour mark to open the scoring for the U's.
Lee Gregory went close in response for the hosts and did equalise when he converted Adam Smith's cross.
U's keeper John Sullivan saved a Matty Pearson effort before Scott McManus was sent off for a second bookable offence.