Theo Corbeanu scored a stunning first MK Dons goal to fire his side to 2-1 victory at Portsmouth and end the hosts’ 10-match unbeaten run in League One.
Mo Eisa was also on target as the visitors cemented their place in the top six.
It could have been different had Connor Ogilvie not missed a gilt-edged early chance by blazing over from six yards.
Eisa opened the scoring in the 20th minute with a cool finish after Matt O'Riley had capitalised on a misplaced pass by Reeco Hackett.
Marcus Harness came close to an equaliser with a 20-yard drive which was inches wide of the post.
Wolves loanee Corbeanu doubled the visitors' lead on the stroke of half-time with a ferocious strike from the edge of the area that crashed into the net off the underside of the crossbar.
Pompey gave themselves a lifeline on the hour thanks to George Hirst's neat first-time finish.
Debutant goalkeeper Jamie Cumming made a brilliant late save to keep out Ogilvie's back-post header and deny the hosts a point.