Ten-man Dons were edged out 2-1 by promotion-chasing Brighton & Hove Albion in an eventful encounter at stadiummk.
Despite a red card for Kyle McFadzean, the Dons kept fighting until the end and were given a golden chance to level matters in injury-time but Carl Baker put him penalty wide of the post.
The fixture was played in front of 21, 345 – a record attendance for a Football League game at stadiummk.
Cody Cropper, Jonny Williams and Nicky Maynard replaced David Martin (hamstring), Samir Carruthers (suspended) and Alex Revell in the starting XI. Carl Baker made a welcome return to the bench.
The Dons started brightly and forced Brighton into some important clearances, while Dean Lewington headed off target from a Josh Murphy free-kick.
After recycling another set-piece, an Antony Kay header set up Darren Potter, who brought a smart save out of David Stockdale from 18 yards on nine minutes.
An acrobatic defensive header denied Williams’ fierce volley causing Stockdale problems as the Dons continued to enjoy the better of proceedings.
The lively Rob Hall then flashed a 25-yard effort wide of the target as the game ticked past the midway point of the first half.
Williams was looking equally impressive alongside Potter in midfield and, shortly afterwards, the Wales international drove forward with purpose before shooting down Stockdale’s throat.
It took Brighton 27 minutes to create their first real opening and, even then, Kyle McFadzean was on hand to head Jiri Skalak’s delivery away from danger.
Ten minutes later saw Cropper make his first save of the afternoon, getting across and pushing James Wilson’s low effort behind for a corner.
Brighton were enjoying their best spell of the game and Cropper had to be alert to thwart Sam Baldock, who had made a clever run and latched on to a forward pass.
The final action of a half the Dons shaded came at the other end when Daniel Powell broke through but was eventually crowded out by three Brighton defenders.
Little had happened in the second half until Brighton were awarded a penalty on 56 minutes after Potter fouled substitute Tomer Hemed, who picked himself up to fire past Cropper.
It was 2-0 on 62 minutes when Hemed rose highest at the back post to head home Skalak’s delivery from the right.
Manchester United loanee Wilson then fired into the side-netting while, at the other end, Maynard and Potter saw shots blocked as the Dons looked for a way back into the game.
Both keepers were called into action in the space of a minute – Stockdale in the Brighton goal to deny Murphy and Cropper to thwart Wilson.
The Dons were back in it on 70 minutes, Antony Kay powering a header from Murphy’s free-kick past Stockdale and into the top corner.
However, the men from MK1 were dealt a blow also immediately when McFadzean was shown a red card for a challenge on Hemed.
Karl Robinson made a double substitution with just over 15 minutes remaining – Jordan Spence and Baker replacing Powell and Williams.
Baker was presented with a golden chance to salvage a point in the final minute of normal time when Dale Stephens was adjudged to have handled in the box, but he put his penalty wide of the post.
MK Dons: Cropper; Baldock, McFadzean, Kay, Lewington (c); Potter, Williams (Baker 76); Powell (Spence 76), Hall (Revell 61), Murphy; Maynard.
Unused subs: Burns, Spence, Tilney, Baker, Bowditch, Emmanuel-Thomas.
Goals: Kay (70).