Gillingham downed promotion-chasing MK Dons with a super performance at Priestfield.
Four different players were on target for the in-form Gills, as they claimed another impressive scalp, following on from wins over Sheffield United and Peterborough.
MK Dons cancelled out Cody McDonald’s early goal but Bradley Dack fired home almost immediately to put the Gills back infront.
The visitors levelled again in the second half, from the penalty spot, but Bradley Garmston made it 3-2 with 15 minutes left before Marquis fired in a fourth.
Victory made it seven unbeaten for the Gills and a second straight win for new boss Justin Edinburgh.
Edinburgh named an unchanged team for the match, following the midweek win at Peterborough.
The Gills were hoping to make it seven games without defeat on Saturday but were facing an MK Dons team vying for a challenge at the top of League 1.
Edinburgh’s side made a fantastic start to the game as McDonald lashed in his 14 of the season, squeezing in a low shot past keeper Ian McLoughlin after Dack had teed him up.
MK Dons came close either side of that, with efforts from Carl Baker and Antony Kay, but the Gills were more than matching their higher-placed opponents.
A smart save from Stuart Nelson denied Samir Carruthers while Dack had a good chance blocked at the other end.
An equalising goal did come though, as Devante Cole struck home from just inside the box with 37 minutes gone. The Gills had struggled to get the ball clear after Dele Alli had threaded it into the danger area.
Cole, on loan from Manchester City, had struck earlier in the season against the Gills for Barnsley, while on loan there.
It took the hosts just a minute to regain the lead though as Gavin Hoyte’s ball found Dack in space and he guided the ball home with a cool finish.
MK Dons made a bright start to the second half but the Gills almost made it 3-1 on 51 minutes through McDonald. His shot bounced off the keeper’s chest and onto the upright. It was another error of judgement by the Dons keeper who had looked nervy throughout.
The visitors remained a threat and only a good tackle from Max Ehmer denied Daniel Powell a sight at goal while sub Ben Reeves fired narrowly over.
Gillingham found themselves outnumbered at the back as MK broke with 25 minutes left but Nelson came to the rescue with a good low save from the busy Reeves. By that point Jermaine McGlashan had been introduced by the Gills.
MK Dons got back on level terms with 68 minutes gone and it was Reeves who fired home from the penalty spot after Hoyte was penalised for a foul on Baker. The Gills defender was fortunate the referee took no further action.
Reeves had another good effort blocked and fired a chance wide while Garmston sent a shot narrowly wide for the Gills.
Garmston had an almost identical chance a minute later, running in from the wing, but this time his shot was precise and found the far corner of the goal to put Gills infront again.
It got better for the Gills with nine minutes left when Dack sent Marquis scampering away and the on-loan Millwall striker fired in low.
Nelson saved late-on from Will Grigg but the Gills were able to see out the game to claim their third straight League 1 win and strengthen their play-off hopes.
Gillingham: Nelson, Hoyte, Garmston, Egan, Ehmer, Loft, Hessenthaler, Galbraith (McGlashan 64mins), Dack, Marquis (Norris 89mins), McDonald. Subs: Martin, Legge, G Morris, German, Dickenson.
MK Dons: McLoughlin, Lewington, Kay, Potter (Hitchcock 85mins), Spence, Baker, Alli, Powell, Carruthers (Reeves 56mins), Andrews, Cole (Grigg 71mins). Subs not used: Hodson, Green, Clarke-Harris, Burns.
Attendance: 5,107 (321 away)