MK Dons failed to keep up the pace with their Sky Bet League Two promotion rivals after going down 1-0 at home to Crewe.
Charlie Kirk's 32nd-minute winner separated the two sides at stadium:mk as Crewe recorded just their second away league victory of the season.
Dons goalkeeper Lee Nicholls did really well to get down and keep Perry Ng's effort out early in the first half.
Down the other end, Ben Garratt pulled off a fantastic save of his own to deny Chuks Aneke when he was bearing down on goal.
The hosts thought they took the lead when Peter Pawlett found the back of the net but his goal was disallowed for offside.
And Kirk took full advantage two minutes later as he completed a fine team goal to give Crewe a surprise lead.
Crewe caught Dons on the counter attack with Kirk powerfully finishing past Nicholls to cap a great move.
The hosts pushed for an equaliser as Alex Gilbey was played in by Kieran Agard, only to be foiled by Garratt, while Nicholls kept out James Jones' audacious chipped effort at the other end.
Substitute Tommy Lowery had Nicholls scrambling to palm his cross-shot over shortly after coming on, while Crewe boss manager David Artell was booked for the fourth time this season for remonstrating with the fourth official as the visitors recorded a rare away win.