Swansea move level on points with United thanks to a 2-1 success at Cheltenham, with Leon Britton hitting the winner eight minutes from time.
But United were boosted by Macclesfield's inablility to beat Boston, with the Silkmen needing a penalty from Mark Bailey in the closing stages to rescue a point in a 1-1 draw.
Northampton kept up their play-off challenge with a 2-0 success over Shrewsbury.
Bristol Rovers drew 3-3 with Darlington in an entertaining match at the Memorial Ground.
A Ryan Lowe brace fired Chester past Bury, while Mansfield ran out 3-1 victors at Kidderminster.
Oxford drew with Leyton Orient, as did Rochdale and Wycombe. The COds played out a goalless stalemare with Rushden.