The Dons closed the gap on second place to just five points following a comfortable 2-0 victory over Scunthorpe United.
The success saw the Dons secure a fourth straight league triumph for the first time since 2012, while they also kept an impressive 21st clean sheet of the campaign.
Rob Hall made his first appearance since returning to stadiummk, replacing Daniel Powell – Lewis Baker also started in place of Dean Bowditch.
Hall played a major part in a flying start for the Dons, receiving from the ball from Baker and drawing a fine save from Luke Daniels – Grigg was on hand to tap home. 1-0
Grigg doubled his and the Dons’ advantage on five minutes, dispatching a penalty with aplomb after Dele Alli had been fouled at the end of a slick attacking move. 2-0
Hall came very close to making it 3-0 on eight minutes when he forced Daniels into a fine fingertip save after cutting in dangerously from the right and letting fly from 25 yards.
The men from MK1 were rampant and they were denied a third on 13 minutes by more good goalkeeping following exquisite interchange on the edge of the area between Hall, Samir Carruthers and, the man who had the shot, Baker.
Hall, terrorising the Scunthorpe defence every time he has the ball, hit the side-netting and Alli saw a volley deflected away as Karl Robinson’s side maintained their unplayable tempo.
Grigg went within a whisker of a 21-minute hat-trick when he sent a shot not far past the left-hand post after clever footwork on the edge of the Iron box.
Daniels denied Grigg’s flicked header finding the top corner on the half-hour mark after the Northern Ireland international had brilliantly met Dean Lewington’s delivery.
Shortly afterwards, a combination of Daniels and the crossbar thwarted Baker, who arrowed a 25-yard effort towards the top left-hand corner after more sumptuous link-up play between Hall, Carruthers and the aforementioned Baker.
The Dons continued to be camped in the visitors’ half until the break, completely dominating possession and looking a constant threat.
They started the second half in a similar vein with Hall and co pushing for a deserved third while, at the other end, a rare foray forward from the visitors saw Gary McSheffrey scoop an effort past the post from a tight angle on 52 minutes.
A quick break presented a chance for the in-form Grigg on 64 minutes, but his low drive was well saved from 15 yards after he had been picked out by the lively Hall.
That proved to Hall’s last involvement as he and Carruthers were replaced by Bowditch and Powell two minutes later with Robinson aiming to keep up the pressure with the introduction of fresh legs.
Following a short corner and some nice footwork, Bowditch fired over from a tight angle while, at the other end, Antony Kay put into a sliding challenge to deny the ball finding Paddy Madden.
The Dons cruised to victory, seeing out the success in a very professional manner in front of a happy home crowd, who were treated to some sensational football under the lights at MK1.
MK Dons: Martin; Hodson, Kay, McFadzean, Lewington (c); Potter, Alli; Hall (Powell 66), L Baker, Carruthers (Bowditch 66); Grigg (Hitchcock 90+1).
Unused subs: Burns, Spence, Green, Cole.
Goals: Grigg (2 & 5).
Attendance: 8,087 (247 Scunthorpe fans).