A calamitous last 10 minutes saw MK Dons throw away a goal lead and end up on the losing side to Portsmouth.
Having been good value for their lead, courtesy of Ike Ugbo's first goal for the club on 20 minutes, Matt Clarke equalised for the visitors with seven minutes to play before some disastrous defending in stoppage time gifted the winner to Conor Chaplin.
In a bid to win his first game, Dan Micciche made five changes and altered the formation for the visit of Portsmouth. Switching to three at the back, Josh Tymon was handed his first start since joining on loan from Stoke City, playing as the left full back. Osman Sow, Marcus Tavernier and Alex Gilbey missed out through injury, and Chuks Aneke was serving the last game of his suspension. Peter Pawlett and Ouss Cisse also made returns to the side.
The change in formation though appeared to have teething problems in the opening 20 minutes. Despite carving the two best chances of the game for Pawlett and Agard, Dons spent most of the opening exchanges trapped in their own half. Lee Nicholls was twice called into action to deny Connor Ronan and then Gareth Evans with a fine diving save, but it was one-way traffic.
Having struggled to see much of the ball in the attacking third though, Dons took the lead on 21 minutes - the first goal of the new Dan Micciche era. Ed Upson sparked the move as he picked out Tymon's run down the left, who in turn looked to pick out Agard in the middle. The striker saw his shot saved at point-blank range by keeper Luke McGee, but Ike Ugbo was on hand to fire home the rebound - his first for the club.
The opener gave the home side a bit more impetus going forwards, but Portsmouth twice had Nicholls at full stretch as they sought an equaliser. First, Ben Close whistled a wonderfully clean strike narrowly over the bar, before Brett Pitman's audacious chip had to be tipped over by Nicholls too.
If Nicholls' stops prevented Portsmouth getting back into it, then McGee's at the other end denied Dons from going in at half time high and dry. Ugbo, with the wind in his sails after scoring, unleashed a fierce effort on the turn from range as he spotted the Portsmouth stopped out of position. But it took a terrific save to deny the effort destined for the top corner. And from the resultant set piece, he kept out Scott Wootton's bullet header to keep the lead to a single goal.
The action continued into the second half and once again, McGee was the man keeping it civil. A quick break from the home side saw Agard battle to the edge of the box and slide in Ugbo, only for the keeper to fly off his line to close the angle and make the save. He was called into action again shortly afterwards when he dived high to his left to tip over Ed Upson's inventive header which looked destined for the corner.
The fragility of a one-goal lead though was highlighted though when the strength of Pitman allowed him to bully his way into the box, and almost pull Portsmouth level, only to see his effort cleared off the line by Scott Wootton.
Portsmouth continued to force the issue, and were only denied by the woodwork when a melee in the penalty area saw gthe ball bounce off the post as Dons struggled to clear.
Eventually though the goal would come for Portsmouth. With seven minutes to go, another corner for the visitors found Matt Clarke at the far post to power his header past Nicholls to secure what they thought would be a point.
But deep into stoppage time, Dons failed to clear another ball into the penalty area, and after a few bobbles, Conor Chaplin was left in space to fire in the winner and heap more misery on the hapless Dons.
MK Dons: Nicholls, Williams, Lewington, Wootton, Brittain, Tymon, Cisse (Ebanks-Landell 80), Upson, Pawlett (McGrandles 58), Agard, Ugbo
Subs not used: Sietsma, Muirhead, Nesbitt, Rasulo, Thomas-Asante
Portsmouth: McGee, Walkes, Hawkins, Clarke, Donohue, Thompson, Close, Evans, Ronan (Chaplin 46), Kennedy (Lowe 46), Pitman
Subs not used: Bass, Deslandes, Widdrington, May, Naismith
Booked: Tymon, Thompson