A collapse in the final half-hour saw Holwell Sports succumb to a first home defeat under new manager Neil Miller to Long Buckby.
For an hour, Holwell looked favourites to add another three points to their recent good home form until a key decision went against them.
With both sides level at 2-2, referee Bullen - who had sent three Melton Town players off last month – awarded a penalty to the visitors when Hendey looked to have won the ball cleanly off Webb.
Johnson’s spot-kick put Buckby ahead for the third time before late indiscipline from the hosts allowed the visitors to leave 502 winners.
Holwell had started brightly, but again found themselves behind to an early goal when Boe finished off good work from Webb.
The hosts’ reply was positive and they almost levelled when Aaron Ridout’s header skimmed the bar and Ross McGarry was unable to get the all from under his feet when unmarked in the six-yard box.
Halim mis-hit his effort for Buckby when well-placed, and minutes later Holwell were level when good work between O’Grady, Cragg and Liam Ambrose created space for Michael Stevenson.
He evaded Wilson to go through on goal, and when keeper Bodycote saved bravely at the midfielder’s feet, McGarry floated the loose ball over Farrow to level.
Play was even, with Holwell having more possession, but Buckby always carrying a threat, especially when wide man Webb was on the ball, and it was the latter who punished Holwell with another clinical finish.
Holwell again responded to the setback and soon found themselves level.
More patient build-up culminated with Ambrose crashing a superb effort over Bodycote, finding the net via the underside of the bar.
The game looked there for the taking, but then came the penalty which gave Long Buckby the lead once more as well as a boost in confidence and energy, while Holwell inexplicably lost all shape and discipline in a desperately poor 15-minute spell.
The visitors took advantage of the massive spaces which suddenly appeared.
Webb, in particular, was enjoying his afternoon and skipped past three defenders to tee up Mellor who finished with aplomb past Challis.
The visitors weren’t finished there and rubbed salt in the Holwell wounds when Webb added a fifth.
General manager Steve Hendey said: “It was very disappointing to say the least.
“We were fine for an hour, and I thought we had the edge in what was a close game.
“But although the referee made a mistake with the penalty, it was entirely down to ourselves that we decided to forgo any kind of discipline or patience with our attacking shape and left massive spaces which the opposition punished us gratefully.”
Holwell slip to 17th, just a point above third-bottom Long Buckby, and head to mid-table Bourne Town on Saturday (ko 3pm).