Chesterfield twice surrendered the lead and conceded deep into stoppage time Cambridge United snatched a 3-2 victory at the Proact on Tuesday night.
Giles Coke made his debut for the Spireites after signing for the club on transfer deadline day and Bradley Barry returned to the side after injury while Sid Nelson was missing after picking up a knock.
Chesterfield got off to a flying start with the opening goal coming in the first minute of the match. Chris O’Grady found himself on the left-hand side of the 18-yard box and put a dangerous cross into the box which was turned into his own net by defender Harrison Dunk.
Early warning signs came from Cambridge when Uche Ikpeazu muscled his way through the Spireites defence, only to see his shot tipped over by Aaron Ramsdale.
Kristian Dennis responded with his first attempt of the game. The striker turned his defender to get off the shot, but it was too weak to challenge the keeper.
Chesterfield continued to look more likely following a neat interchange of one-twos between Dennis and Louis Dodds down the left-hand side. Dennis managed to float in another dangerous cross but a free-kick was given for an altercation in the box.
Cambridge found a way back into the game through an Alex Whitmore own goal (19). A shot from distance was parried by Ramsdale, only as far as Liam O’Neil whose low driven cross across the face of goal was turned in by Whitmore after a touch from Ikpeazu.
Chesterfield’s next chance came when Joe Rowley looped a free kick into the 18-yard box. The ball was cleared but only as far as Dodds, whose shot was blocked and sent out for a corner.
Cambridge began to grow into the game more when Ikpeazu again shrugged off multiple defenders, only to see his left-footed striker fly high and wide. Brad Halliday went close a moment later with his shot from distance spinning wide of the left-hand post.
Chesterfield began the second half as brightly as they did the first, with Robbie Weir’s pin-point delivery meeting the rising header of the un-challenged Dennis (55), who placed his accurate effort into the top right corner of the net.
Louis Reed put a looping free-kick over the defensive wall, forcing a save around the post from David Forde.
Cambridge again found a way to come from behind to level it as Weir was adjudged to have fouled Billy Waters. The linesman flagged for a penalty kick and Ikpeazu (68) converted from the spot, shooting to Ramsdale’s right.
Cambridge enjoyed their new lease of life with another shot moments later, this time coming from George Maris after the ball was given away by Rowley. The shot went straight towards Ramsdale and the keeper collected it with ease.
Hoping to find a winning goal, Jack Lester made two changes in the 70th minute, bringing on Josh Kay for Rowley, and Dylan Mottley-Henry for Dodds.
Joe Dunne also mixed things up with 12 minutes to go, introducing David Amoo in place of O’Neil.
Jevani Brown posed a number of threats late on, but each attempt was comfortably dealt with by Ramsdale.
With six minutes to go, Lester made his final substitution, bringing Jak McCourt onto the field to make way for Coke.
Brown continued to look likely late on as he fizzed the ball across the face of goal, with Maguire making a clearance.
The fourth official signalled for five minutes of added time and in the game’s dying embers, Dennis found the back of the net but the goal was disallowed for handlingl.
At the other end, Ramsdale was forced to push a looping cross over the bar. From the resulting corner, Cambridge found a winner in the final seconds of the game, when Dunk reacted quickest to convert a loose ball into the net off the underside of the bar.
The result means Chesterfield stay in the relegation zone and three points adrift of Crewe in 22nd place, while Barnet remain bottom of the table.
Chesterfield: Ramsdale, Barry, Whitmore, Maguire, Weir ( C ), Reed, Dodds (Mottley-Henry 70), O’Grady, Rowley (Kay 70), Dennis, Coke (McCourt 84)
Cambridge: Forde, Halliday, Deefan ( C ), Taylor, Waters, Ikpeazu, Dunk, Taft, O’Neil (Amoo 78), Maris, Brown
Attendance: 4,276 (220 away)