LEYTON Orient twice came from behind to win 3-2, when Dons should really have been home and dry at the break.
Dean Lewington’s spectacular eighth minute opener was soon cancelled out by Jimmy Smith’s well-struck effort six minutes later, before Jabo Ibehre got on the end of a Rowan Vine cross to put Dons back in front on 23.
Dons then missed a host of chances before Smith headed home a second equaliser on 39 minutes, and Orient turned the tide after the break.
In a limp second 45, substitute Jonathan Tehoue broke through the dogged Dons defence to slot the winner past David Martin with 17 minutes remaining, and the home side offered little in retort.
Peter Leven returned to the starting line-up after serving his one match suspension for being sent off against Sheffield Wednesday and Tom Flanaghan - recently recalled from his loan spell at Kettering Town - was posted at centre-back alongside Sean O’Hanlon.
It took Stephen Gleeson six minutes to lash home a volley in the corresponding fixture last month, and it was his shot from similar range that earned his side a corner from which they would take the lead again.
O’Hanlon was unable to get on the end of Leven’s delivery, but the clearance fell nicely to Lewington who composed himself 25-yards and found the top corner of Jamie Jones’ net with a spectacular left-footed strike, with the keeper fully rooted to his spot.
But it was not long before Orient were back on level terms with their first effort on target. Mathias Doumbe - playing at right back - was caught horribly out of position, allowing Dean Cox acres of space down the Orient left, and he picked out Smith on the edge of the box to curl the ball past Martin.
The goals continued to rain in as Dons once again took the lead. A quick free-kick from Leven out-foxed the O’s defence and found Vine in the box, and making it to the byline, he cut back perfectly for Ibehre to fire home side-footed, with a little help from the underside of the crossbar to give Dons a 2-1 lead with 22 minutes played.
Dons then produced their best move of the game when Flanaghan played a fantastic pass to unleash Vine down the left, and first time, the on-loan QPR man fired over a cross for an unmarked and well-placed Ibehre in the centre - but the big front man couldn’t control his volley and it went just wide.
With Orient in pieces at the back, Keanu Marsh-Brown really should have doubled Dons’ lead on 35 minutes, but his shot - after some good work by Chadwick that drew men out - was well over the bar.
But just when Dons looked like running riot, Orient pinned them back six minutes from the break. Again caught too narrow, Doumbe allowed Cox plenty of room, and he cut back to find Charlie Daniels - and his cross then found Smith at the far post who nodded in.
With the entire Dons team convinced it was offside, even Karl Robinson turned away in acceptance of the decision, which didn’t come - queue the protests and expressions of disbelief from the Dons coaching staff.
Robinson made his feelings well known to referee Brendan Malone at the half-time whistle, with the Dons faithful letting him know what they felt with some choice chanting.
But after a thrilling first half, the second, for the most part, was a quiet affair - both on and off the pitch.
Daniel Powell replaced goal scorer Ibehre, and came close to breaking the deadlock six minutes into the second half. Chadwick’s neat through ball allowed the youngster to power into the area and brilliantly round keeper Jones, but Daniels slid in at the key moment to block the shot at the source.
With 20 minutes remaining Marsh-Brown switched to the left and immediately showed off his pace, breaking in behind Andrew Whing and sending in a low ball across the face of goal, but no-one was there.
And Dons were made to pay for their missed chances when substitute Jonathan Tehoue broke clear and latched onto the end of Elliot Omozusi’s pass to slot past Martin with only 17 minutes left to play.
Flanaghan was having a near faultless game at the back, and he nearly pulled Dons level 60 seconds later with a header that was acrobatically saved by Jones, and O’Hanlon’s follow-up was hacked off the line.
Looking to the bench for inspiration, Robinson threw on Jude Stirling for the final five minutes, who lifted the crowd and Dons’ sense of urgency.
He won Dons a corner from which his team came closest to equalising when O’Hanlon towered above his marker to head the ball goalwards, but O’s skipper Stephen Dawson got in the way on the line. It looked suspiciously like handball, but the referee just signalled for another corner.
But nothing came of it as Dons slipped to just their third home defeat of the season and now occupy eighth place in League One.