Berkhamsted lost their place at the top of the SSML Premier Division table after suffering a disappointing 2-0 defeat at home to AFC Dunstable.
Berko pulled in their biggest crowd of the season, but had on off day against their promotion rivals who were certainly up for the occasion.
Before the match, league representative Bob Flight presented the Team of the Month award to Berkhamsted, but they were certainly not at their best as Dunstable took full advantage.
Berko boss Mick Vipond gave a first start to Dale Turney in midfield and Jamie Gavin was moved into the defence as Kyle Lincoln was injured in the previous week’s game with Colney Heath.
Josh Chamberlain might have given the hosts the lead in the opening exchanges, but the chance was lost and the visitors counter-attacked with a vengeance.
Jamie Warne hit a wonderful shot to give Dunstable the lead, with some of the crowd still arriving through the turnstiles.
And it was the same man who scored again to double Dunstable’s lead at a psychologically important moment just before the interval.
This time he ran down the middle through a series of half challenges before slipping a low shot into the net.
Berko had trouble in the first half containing the giant visiting forwards, but made a better job of it after the interval.
Comrades striker BJ Christie got more involved in the game as the half went on – one shot was held and he later sent over a cross for new signing Dylan Gittings whose header was brilliantly tipped over the bar by Jamie Head at the Canal End.
At the other end, Carl Tasker pulled off a good save to deny Leon Simpson and Jimmy Hartley put the loose ball wide.
Christie headed over and Adiel Mannion hit the bar as Berko’s day reached a frustrating conclusion, with Sun Postal Sports overtaking them at the summit of the division.