The Dons salvaged a deserved point deep into injury-time thanks to a stunning solo effort from Daniel Powell.
The equaliser had been coming after fellow substitute Rob Hall had come close when he brought the best out of Frank Fielding while Jake Forster-Caskey couldn’t turn home the winger’s teasing cross.
Karl Robinson named an unchanged side for the clash at Ashton Gate, with Jake Forster-Caskey and Simon Church continuing in midfield and attack respectively.
Dean Bowditch missed out through injury while Samir Carruthers served his final game of a three-game suspension. Cody Cropper, Matt Upson, Joe Walsh, Mark Randall , Dale Jennings and Darren Potter remained sidelined through injury.
Before either side could take control, the hosts hit the front in the sixth minute when Bobby Reid robbed possession, raced down the right and crossed for Jonathan Kodjia to tap home from close range.
Reid flashed an effort wide shortly afterwards as the Reds tried to stay on the frontfoot while, at the other end, Ben Reeves sent a low drive off target on 15 minutes.
A superb touch from Reeves was the catalyst for a Dons attack midway through the half but, after freeing Josh Murphy and receiving a return pass, the No.10’s cross was comfortably gathered by Frank Fielding.
After an evenly-contested spell, Kodjia started a quick counter for City down the left on 40 minutes and crossed for the arriving Luke Freeman, who somehow blazed over from 10 yards when well placed.
Kodjiam, himself, was denied courtesy of a decent stop from David Martin as the game entered injury-time at the end of the first half.
Murphy threatened at the start of the second period but, after beating Mark Little, his left-wing delivery was taken by Fielding, who then watched a shot from the Norwich City loanee go over the top.
The Dons were enjoying their best spell of the game and Forster-Caskey back-heeled into the path of Reeves, who brought the best out of Fielding from the edge of the box.
Carl Baker then saw a shot blocked from distance after cutting in from the right before Simon Church tried to get on the end of a Dean Lewington cross which hit the post, but it wouldn’t have counted anyway as the offside flag was up.
Rob Hall and Nicky Maynard were introduced, the latter against his former club, as the Dons looked for a spark in attack with 20 minutes remaining.
Hall, his usual busy self, tested Fielding with a stinging 25-yard drive which was pushed around the corner – Kyle McFadzean fired the recycled resulting corner inches past the right-hand post.
The men from MK1 were knocking on the door and they came so close to a leveller but Forster-Caskey couldn’t quite reach Hall’s dangerous delivery on 79 minutes.
Reeves volleyed down the throat of Fielding and Hall saw a shot well blocked as the Dons continued to push for an equaliser.
Their pressure was finally rewarded in the second but last minute of added time when substitute Powell beat his man and curled a superb effort into the far corner from 20 yards.
MK Dons: Martin; Spence (Hall 69), Kay, McFadzean, Lewington (c); Poyet, Forster-Caskey; Baker, Reeves, Murphy (Powell 80); Church (Maynard 69).
Unused subs: Burns, Hodson, Rasulo, Gallagher.
Bookings: Lewington, Forster-Caskey, Poyet.
Powell: Powell (90+4).
Attendance: 14, 535 (425 Dons fans).