Isaak Davies turned in a 92nd-minute winner as Cardiff City broke Wimbledon's resistance to remain second in League One and continue new boss Brian Barry-Murphy's unbeaten start as manager.
A game that had often been pleasing enough on the eye but contained little goal threat had seemed to be petering out into a draw.
But in time added on, Chris Willock's cross was only cleared as far as David Turnbull on the edge of the Dons box and his shot was diverted into the net by the leg of Davies.
Even then it took an exceptional save by Cardiff goalkeeper Nathan Trott to secure all three points as Antwoine Hackford sent a low shot angling towards the far corner.
Cardiff came into the game having now won just two of their past 26 away league outings and, although they left it late against Wimbledon, will hope this victory will be a turning point.
The two clubs' only previous encounter was a 1-0 win for the Bluebirds in the 2015-16 League Cup first round, so here was a chance to make a statement in the league.
Cardiff started brightly and had a strong appeal for a penalty when Steve Seddon appeared to scissor through the back of Joel Colwill, making just his third league start for the Bluebirds, but stony faced referee David Rock was unmoved.
Jake Reeves provided Wimbledon with their first effort at goal, but the midfielder's dipping shot sailed just over the crossbar, while at the other end Yousef Salech was equally close with a header.
Wimbledon boss Johnnie Jackson was forced into an early change when centre-back Joe Lewis, who had been struggling for some time after being landed on by the 6ft 5in Salech, was replaced on 27 minutes by Riley-Jay Harbottle.
Cardiff had enjoyed the lion's share of the first half and should have been ahead at the break, but Ollie Tanner's left-wing cross was a foot too far in front for the advancing Joel Colwill to reach.
That was Tanner's last contribution as he collided with an advertising board soon after and was replaced by Chris Willock.
After a first half that was glaringly bereft of a single shot on target, Dons goalkeeper Nathan Bishop almost rectified that by gifting an opener to Rubin Colwill when he stumbled on the ball but recovered just in time to clear.
Cian Ashford then clattered the ball off the right post, although the Cardiff winger had already been pinged for an infringement.
Finally, in the 56th minute, a keeper was called to make a save, although Alistair Smith's ambitious 35-yard daisy-cutter was easily collected in the centre of the Cardiff goal by Trott.
As the game ticked into the final half-hour both managers had seen enough, with Jackson and opposite number Barry-Murphy making three changes apiece.
One of those changes, Callum Robinson had a goal-bound shot blocked by Harbottle - with the Cardiff striker adamant the Dons defender had used an arm, a plea waved away.
When the ball broke kindly to Omar Bugiel, it seemed as though he would snatch a late victory for Wimbledon only for the off-balance substitute to snatch at the chance and watch the ball spiral wide.
Robinson had a similar, even later opportunity, but ballooned an inviting cross over the Dons bar with his head.
His blushes were spared by Davies' strike, sticking out a leg to divert Turnbull's shot that may - or may not - have already been heading into the back of the Wimbledon net.
AFC Wimbledon: Bishop, Asiimwe, Seddon (Sasu 89'), Reeves, Johnson, Orsi (Bugiel 63'), Smith, Stevens (Hackford 63'), Hippolyte (Browne 63'), Lewis (Harbottle 28'), Ogundere. Subs Not Used: McDonnell, Maycock.
Cardiff City: Trott, Kpakio, Fish, Lawlor, Bagan (Chambers 82'), Wintle, J.Colwill (Turnbull 63'), R.Colwill, Ashford (Davies 63'), Tanner (Willock 45'), Salech (Robinson 63'). Subs Not Used: Turner, King.
