John Coleman's team had not lost in the league since a 3-1 defeat by Stevenage. But next Saturday Stanley face their toughest test when travelling to second-placed Exeter City.
Win that game and the fans can really start dreaming about promotion to the Football League.
The home supporters had to wait until the 77th minute of a dour game to see the winning goal by Ian Craney, his ninth of the campaign to turn one point into three and leave Cambridge languishing in the bottom half of the table.
Certainly the roles have been reversed since United won 3-1 at the Abbey Stadium back in August. Since then they have gone downhill while Accrington have laid the foundations for a promotion back into the big time for the first time in nearly 50 years.
Chances for both teams were at a minimum throughout the contest but in former Altrincham star Craney the Lancastrians have a player to change games.
Accrington's latest success means they are now eight points clear of Exeter but more importantly have opened up an 11-point advantage over third-placed Grays Athletic.
Craney's goal spared the blushes of team-mate Peter Cavanagh following the Stanley defender's wasted opportunity to put his team ahead with a second-half penalty that was awarded for a foul on Andy Mangan, but which was saved by Scott Howie.
Craney repaired the damage turning in a pass from strike partner Paul Mullin with only 12 minutes left.