Two stoppage goals saw Barnet beaten 3-1 by Grimsby Town at The Hive on Saturday afternoon.
The Mariners had led through Christian Jolley’s first-half strike but Barnet looked to have done enough to claim at least a point with a spectacular equaliser from substitute Conor Clifford, only to be undone by late goals from Craig Disley and Jon-Paul Pittman.
Ahead of the game, Martin Allen named three changes to the side that were narrowly beaten by Wrexham last time out.
New signing Michael Gash made his first start for the club since joining in January, replacing the suspended John Akinde up front as the Bees number nine missed his first league game of the season.
Meanwhile, David Stephens returned to the heart of the Barnet defence in place of Jack Saville for the first time since the Bees last faced Grimsby four weeks ago, with Luisma Villa lining up on the right side of midfield as Conor Clifford dropped to the bench.
The visitors came out of the blocks quickly and set the early pace of the game, going close on 12 minutes when a cross from the right picked out Nathan Arnold ghosting into the box but the winger’s half-volley fizzed just wide of the post.
They troubled the Barnet defence again after a quarter of an hour, when Sam Togwell was forced to chest away a cross into the box before hooking the ball off the goal line and away to safety.
Barnet’s first chance came just one minute later, when a push on Michael Gash provided Luisma Villa with a free-kick 25 yards from goal but the Spaniard was unable to get his effort on target as the ball flew wide.
He had another set piece opportunity on 22 minutes on the edge of the penalty area after Sam Togwell was fouled in collecting the rebound from a Michael Gash shot, a foul for which Craig Clay was the first man in the book, but this time Villa could only fire his shot into the Grimsby wall.
The Mariners were continuing to look dangerous, and took the lead on 27 minutes with a close range finish from Christian Jolley after Jack Mackreth had done well to beat Elliott Johnson to a ball on the byline once a Lee Cook pass forward had been charged down.
Barnet were forced into their first change of the afternoon shortly after the half-hour mark, with Togwell being replaced by Clifford following the knock he had received earlier on.
The home team had Graham Stack to thank two minutes before the break, when the goalkeeper got down well to his right to palm away a shot from distance by Lenell John-Lewis to ensure that it remained 1-0 at half time.
Barnet came out for the second half with a renewed sense of purpose, and had their first chance on 55 minutes when Charlie MacDonald collected a backheel from Curtis Weston before firing over on the volley.
They did not have to wait long for an equaliser however, as Conor Clifford drew them level just one minute later with a wonderful curling shot from 25 yards that James McKeown could not keep out of the top corner despite getting his fingertips to the shot.
The goal suddenly put Barnet on the front, with the introduction of Luke Gambin for Lee Cook on 71 minutes injecting some added pace into their attacking play.
A calf injury to David Stephens then forced the Bees into their final change of the afternoon as Jack Saville came on in his place.
As a gripping game entered its closing stages either side could have taken the lead during a frantic final few minutes of normal time, with Graham Stack producing a superb diving save to tip away a John-Lewis header before John McKeown responded with a spectacular stop of him own to claw away a Luisma curler that appeared destined for the top corner with four minutes left.
However, just as the fourth official signalled four minutes of additional time to be played it was Grimsby who won it, as captain Craig Disley stole into the box to prod into the net after Barnet had failed to clear a free kick.
Substitute Jon-Paul Pittman then sealed the three points for the Mariners in the dying moments, tapping in from close range after Stack had parried John-Lewis’ initial effort from inside the box.
Luisma forced another sprawling save from McKeown with a free kick on the edge of the box, but it was not enough as Barnet fell to a 3-1 defeat.
Following the result the Bees’ lead at the top has been reduced to just one point, with a trip to Altrincham to follow next weekend.
Barnet FC: Graham Stack; Andy Yiadom, David Stephens (Jack Saville 79), Bondz N’Gala, Elliott Johnson; Luisma Villa, Sam Togwell (Conor Clifford 33), Curtis Weston, Lee Cook (Luke Gambin 71); Charlie MacDonald (c), Michael Gash.
Grimsby Town: John McKeown; Carl Magnay, Aristote Nsiala, Shaun Pearson, Gregor Robertson; Jack Mackreth, Craig Disley (c), Craig Clay (Danny Parslow 90), Nathan Arnold; Christian Jolley (Jon-Paul Pittman 70) Lenell John-Lewis.