MK Dons produced an unlikely comeback as they battled back from two goals down to win 4-2 against Gillingham.
The Dons made a winning start thanks to second-half goals from Will Grigg, Kyle McFadzean and an own goal from Aaron Morris.
After going two goals ahead in the first 30 minutes, an injury to Cody McDonald, stretchered off after the break, and then a bizarre substitution by Gills boss Peter Taylor that saw goalkeeper Stuart Nelson replaced at the break, proved the visitors' undoing.
Gillingham applied the early pressure and took the lead inside seven minutes. McDonald, who netted 17 goals last term, raced free of McFadzean to produce a neat finish into home goalkeeper David Martin's far corner.
McDonald was also involved in his side's second goal in the 28th minute as Martin bundled the former Norwich striker over inside the penalty area.
Former AFC Wimbledon target man Danny Kedwell finished from the spot to double his side's lead.
The home side pulled a goal back a minute before the break as goalkeeper Nelson failed to hold an aerial ball, which then hit Kortney Hause to bounce despairingly over the line.
The error from Nelson proved to be his last meaningful involvement in the game as he was replaced for the second 45 minutes by Glenn Morris.
The decision backfired on Taylor though as Gillingham shipped three unanswered goals after the break.
Karl Robinson's men turned the game on its head inside a stunning five-minute spell.
Brentford loanee Grigg started the comeback when he headed home from Danny Green's cross in the 67th minute.
Green, who signed a permanent deal in the summer following a loan spell last term, then provided for McFadzean, who looped his header over Morris to earn his first goal for the club just minutes later.
The comeback was secured for the Dons when another Green set-piece took a deflection off Gills midfielder Aaron Morris and bounced over the goal-line.