London Colney suffered their first defeat to Hadley for six years after losing 1-0 in the South Midlands Premier Division on Saturday.
Early on in the game Bobby Armstrong made a timely clearance off the line when a effort from Jordan Watson was heading goalwards. At the other end Armstrong sent over a cross which keeper Tom Le Tissier just about gathered off the head of Matt Newman as he closed in.
Dan Millard had a effort saved by Colney's Charlie May while Jimmy Hartley was blocked inside the box by two defenders as he closed in on goal after a surging run. A free-kick taken by Shay Knosrowshahi found Chris Beels at the back post but his header flew just wide of the upright and then Kieran Smith had a effort blocked by Armstrong.
The second half was only a few minutes old when Newman made a good run towards goal and found Jimmy Hartley but his shot flew just over the crossbar. At the other end both Jordan Watson and Dan Millard had shots at the Blueboys goal but they went just wide of the target.
A poor kick from Le Tissier found Newman and after creating space for himself his shot curled just wide of the far post. From a corner, Shaun Murphy saw his close-range shot deflected just wide and then from another set piece Murphy's header was pushed away by Le Tissier and cleared off the line by Tom Milton.
Newman had another effort go close and the match seemed to be heading for a goalless draw.
But the hosts snatched the points when Kieran Smith blasted the ball past May at the second attempt.
London Colney Reserves drew 1-1 away to Kent Athletic with a goal from Josh Galloway whilst London Colney Blues won 2-1 against Harpenden Rovers with efforts from Johnny Armitt and Eamon Rogers.
London Colney host Cockfosters on Thursday before entertaining Colney Heath this weekend.