London Colney suffered their first home defeat of the season after losing 3-2 to ten-man Cockfosters in the South Midlands Premier Division last Saturday.
Cockfosters made a bright start and took the lead after 14 minutes when Ben Hart fired home.
It got even worse for the Blueboys on the half-hour mark when Ioannis Varouxakis waltzed through the defence and scored from close range.
The hosts were handed a route back into the match after winning a penalty when Spencer Clarke-Mardel’s shot was handled on the line by Cameron Currie, who received a red card. Greg Shaw converted the spot-kick to halve the deficit.
Cockfosters extended their lead midway through the second half when Bobby Spears headed past goalkeeper Tom Gowans.
The Blueboys responded and almost pulled a goal back through Shaw but his header was blocked on the line.
But London Colney did add a second goal when Jon Clements’ corner was headed home by Shaw with 15 minutes left.
The hosts almost equalised but Dave Parkinson’s header was saved by Austin Byfield.
The side travel to Newport Pagnell Town in the FA Vase on Saturday.