Rugby Town's promotion hopes suffered a huge blow as Eynesbury Rovers won via a last minute penalty at Butlin Road.
Town looked to be cruising having established a two goal lead within twenty minutes, but a defensive horror show in the run-up to the interval saw them concede three to end the half behind.
Eli Bako then marked his Rugby debut with an equaliser just past the hour mark, but Rovers had the last laugh after their 88th minute winner.
Bako replaced the suspended Dom Perkins in Town's midfield in the only change from the previous weekend's draw at home to Pinchbeck.
The hosts started well, with Edwin Ahenkorah creating the first chance of the game for himself by turning neatly in the box before firing in a rising effort that Rovers keeper Jamie Greygoose managed to catch.
Justin Marsden's low shot drifted just wide and a Lewis Rankin strike lacked power, as the good start continued, with Eynesbury's only attacking foray of note seeing Matt Hill cut out Jordan Brown's cross from the right.
The opening goal came on 15 minutes after Charlie Evans had struck the bar from twenty yards, allowing Simeon Tulloch to follow up and power home the rebound.
Curtis Hartley did lift one over the bar at the other end, before Rugby extended their advantage when Loyiso Recci headed Rankin's corner back across to Evans to head home from close range.
The unexpected comeback from the away side started on 37 minutes, when Hill failed to deal with a high cross and Brown eventually stabbed the ball over the line after a goalmouth scramble.
Danny Draper was soon levelling the scores when he was given far too much time and space in the box before firing home. Spurred on by their quickfire double the visitors probed for a third before half-time, and Jack Warwick, Draper and Steve Gentle all went close for them, before Gentle headed Draper's cross into the path of Brandon Williams to nod in.
Rovers made the brighter start after the teams returned to action, with Draper blazing over after Brown had beaten Recci for pace down the channel. However it was all-square when Greygoose did not read Ahenkorah's looping ball into box which provided Bako with the opportunity of a simple finish.
Rankin's effort was then blocked on the line by Owen Clarke, with Dan Summerfield striking one way over as Town pushed for a fourth.
Greygoose also turned a Rankin free-kick round the post and Liam Francis headed over Tulloch's corner from the left.
The game was settled though when Recci was adjudged to have pushed Brown in the penalty area, and Jordan Jarrold rolled in the resulting spot-kick.
Line-up: Hill; Recci, Summerfield, Francis; Rosser, Tulloch, Bako, Marsden (Steele), Rankin (Dawson); Evans, Ahenkorah. Subs not used: Connor, Kavanagh, Holloway. Booked: Rosser, Summerfield.
Eynesbury line-up: Greygoose, Clarke, Jarrold, Hartley, Ducket, Warwick, Draper, Sinclair, Gentle, Brown, Williams.