MANSFIELD Town lost further ground on the play-off places after they threw away a lead to lose 2-1 at home to Cambridge United.
It had looked bright for Stags after top scorer Matt Green scored his 11th goal of the season on 55 minutes to fire Mansfield ahead following a perfect through-ball by Lindon Meikle.
But Stags switched off badly and allowed Harrison Dunk to bag a brace inside the space of five minutes to seal the game for the promotion-chasing visitors.
The equaliser will cause particular concern for boss Paul Cox as Luke O’Neill allowed Dunk to ghost past him and fire in from a tight angle as he attempted to let the ball run out for a goal-kick on 57 minutes.
The turnaround was complete on 62 minutes when Dunk sprung the offside trap before squeezing the ball between the diving Marriott and into the goal
Mansfield responded well as they attempted to find away back into the contest with Meikle, Howell and Dyer all testing Naisbitt.
But despite long periods of pressure Stags, who have not kept a clean sheet for 10 games, were unable to find a way of cracking the resolute Cambridge rearguard.
The defeat leaves Stags further adrift of the last play-off spot and in desperate need of three points in their next league outing against AFC Telford.
Boss Paul Cox made three changes to his starting line-up as Stags looked to erase the bad memories after their midweek hammering at Fleetwood Town.
Top scorer Matt Green made a welcome return to the side at the expense of Louis Moult after shaking off the sickness bug which swept through Field Mill this week.
Defender Kieron Freeman, signed on loan from Nottingham Forest on Friday, and winger Nick Hegarty, who was signed from St Mirren also on loan, were given places in the starting line-up.
Cambridge came to Field Mill on the back of a thumping 6-2 win at Hayes and Yeading and with just one defeat in their last 15 outings.
Cambridge had the first effort of the game when an Ashley Carew free-kick clipped the back of team-mate Luke Berry before floating out for a goal-kick.
Stags captain Adam Murray knew he would have to be careful when he was booked after just six minutes for a foul on Kevin Roberts.
The fifth-placed visitors were a breath away from breaking the deadlock on 14 minutes when Berry burst into the box before cracking his effort against Marriott’s right post.
Michael Wylde then saw his strike blocked for a corner as he attempted to steer the rebound home.
The lively Carew then curled a 16th minute free-kick wide of Marriott’s goal as the confident U’s began to turn up the pressure.
Tom Shaw fired another warning shot for Cambridge on 23 minutes after a layoff from Gash left Shaw in space 25 yards out.
At the other end struggling Stags finally managed to register their first attempt on Naisbitt’s goal a minute later when new-boy Kieron Freeman headed an O’Neill cross wide from eight yards.
A flowing move involving Dyer and Meikle down the right wing could have seen Mansfield take the lead on 26 minutes as the home side finally began to come back into the game.
But Meikle’s final ball was poor as he failed to pick out a well-placed Matt Green in the box before the ball was cleared to safety.
Stags should have opened the scoring on the half hour mark when Dyer and Meikle once again combined well.
Meikle whipped the ball in from the left before Dyer knocked the ball down into the path of Hegarty.
But, with the goal at his mercy, the former St Mirren player somehow skied his effort over the bar when it would have been easier to score.
Stags continued to turn up the heat and again came close to opening the scoring on 39 minutes when Naisbitt was caught out of position as he attempted to cut out a long ball through midfield.
Dyer beat the shot-stopper to the ball on the right corner of the box before squaring the ball into the danger area as Green sensed a tap-in into an empty net.
But defender Tom Shaw did just enough to block Green to the ball and his scuffed effort was gobbled up by the hastily retreating Naisbitt.
Stags finally opened the scoring on the 55th minute when excellent work by Lindon Meikle won the ball back in central midfield.
The England C player then threaded the perfect pass into the path of Matt Green, who rounded the advancing goalkeeper on the edge of the box before rifling home for his 11th strike of the season.
It was the calmest of finishes and showed just what Stags had been missing against Fleetwood.
But it was despair for Stags just two minutes later when some sloppy defending allowed the visitors to level the contest.
O’Neill was caught napping as he attempted to let the ball run out for a goal-kick. But Harrison Dunk read the situation well and squeezed between the sleeping defenders to fired past Marriott from the tightest of angles.
Meikle came close to putting Mansfield ahead again on 61 minutes when he linked up well with Dyer.
Dyer played the wingman in down the right hand side, but Meikle was leaning back as he attempted to fire into the top corner, before finding the empty seats of the Quarry Lane end.
It was a costly miss as the visitors took the lead on 62 minutes when Dunk bagged his second of the game.
A pin-point pass allowed Dunk broke the Stags offside trap. And despite a poor first touch Dunk still had the time and space and to squeeze a shot past the outstretched arm of Marriott and into the bottom corner.
The dangerous Meikle seemed to be Mansfield’s best chance of levelling the game as he once again warmed the hands of Naisbitt with a shot from distance on 64 minutes.
Howell saw his shot saved by Naisbitt after a Murray cross was brought down well by Dyer and laid into the path of the midfielder on 74 minutes.
Substitute Louis Moult came close on 75 minutes when he turned an O’Neill cross just over the bar while under pressure from his marker.
Ross Dyer then wasted a good chance from a wide angle moments later as Mansfield began to push the visitors further and furtherback.
Dyer really should have levelled the contest with 11 minutes to go when he was picked out by O’Neill at the back post.
But he failed to find the target as he directed his header over the bar as Naisbitt watched on.
Stags won their first corner of the contest on 86 minutes as they looked for a way back into the match.
Green fired well over from distance in injury-time and with it went Mansfield’s hopes of saving a point.
MANSFIELD TOWN: Marriott, O’Neill, Futcher, Sutton, Freeman, Meikle, Murray, Howell, Hegarty (Moult 68 mins), Green, Dyer. Subs not used: Redmond, Thompson, Connor, Bolland.
CAMBRIDGE UNITED: Naisbitt, Roberts, Coulson, Wylde, Shaw, Gash, Carew (Charles 63 mins), Dunk (Patrick 80 mins), McAuley, Jarvis, Berry. Subs not used: Marriott, Hudson, Thorpe.
STAGS MAN OF THE MATCH:Luke O’Neill.
REFEREE: Darren Bond of West Lancashire.
ATTENDANCE: 2,046 (237 away)