The Dons picked up a hugely-impressive point at promotion favourites Hull City to maintain their place outside the bottom three.
Daniel Powell, Rob Hall and Alex Revell returned to the starting XI at the expense of Dean Bowditch, Jonny Williams and Nicky Maynard.
Carl Baker travelled and took part in the warm-up but not adjudged to be quite ready for the squad, while Jake Forster-Caskey (ankle), Joe Walsh (hamstring) and Matt Upson (hamstring) remained sidelined.
The first chance of the afternoon fell to Hull City and Mo Diame, who sent an ambitious volley well wide of David Martin’s goal.
At the other end, Revell’s flick-down caused a problem in the Tigers’ box but unfortunately no-one could meet it before Powell fired over from 20 yards on six minutes.
The Dons settled well with the team looking compact at the back and dangerous going forward, but Steve Bruce’s side have got quality throughout and a smart interchange between Abel Hernandez and Ahmed Elmohamady forced Antony Kay to turn behind almost 20 minutes in. From the resulting corner, Curtis Davies flicked on but Revell and, ultimately, Martin were alert to the danger.
Some superb footwork from Rob Hall created a crossing chance for Josh Murphy, who almost found Powell with a ball to the back post but Moses Odubajo got an all-important touch.
The next chance didn’t arrive until 31 minutes when the hosts worked the ball well on the edge of the Dons’ box and set up Elmohamady, who dragged his effort off target from 20 yards.
A knock-down Hernadez presented a shooting opportunity for Chuba Akpom with five minutes to go until the break but the England youth international flashed his 25-yard effort wide.
As a solid first half for the Dons came to a close, George Baldock did well to put pressure on Diame, who subsequently headed off target at the back post.
Hull started the second half strongly and a dangerous Diame ball flashed across the box before Martin comfortably gathered a shot from the same man.
However, it was the Dons who hit the front on 51 minutes, Kay running on to Hall’s corner and powering a header past Scotland international Allan McGregor from 12 yards.
After missing a clear handball by Hernandez, the referee awarded a free-kick for a foul by Carruthers – Sam Clucas stepped up from the resulting set-piece and curled home from 20 yards to level matters.
Akpom headed over a glorious opportunity from eight yards just past the hour mark before, at the other end, Murphy forced a save from McGregor.
Buoyed by his goal, Clucas tried his luck from 25 yards and tested Martin before Akpom fired over the top from a similar distance.
That proved to be Martin’s last involvement as an injury forced him to be replaced by Cody Cropper, but it was the scorer, Kay, who came to the Dons’ rescue shortly afterwards when he threw his body at a shot.
With 10 minutes remaining, the Dons broke through the pacey Murphy and he fed Powell but, after gathering and creating a shooting opportunity, McGregor was up to the task from close range.
Hull were the side forcing the issue as the game ticked into injury-time but the Dons’ defence was holding firm and they had a chance of their own through Revell, who forced a stop from McGregor 25 yards out.
A monumental block in the last of eight added minutes from McFadzean ensured the Dons left with an important point after a hugely whole-hearted performance.
MK Dons: Martin (Cropper 71); Baldock, Kay, McFadzean, Lewington (c); Potter, Carruthers; Murphy, Hall (Bowditch 76), Powell (Williams 83); Revell.
Unused subs: Spence, Reeves, Emmanuel-Thomas, Maynard.
Bookings: Carruthers, Kay.
Goals: Kay (51).
Attendance: 16,183 (298 Dons fans).