New Barnsley boss Lee Johnson named two changes to the side which beat Scunthorpe 1-0 away from home in midweek.
Milan Lalkovic and Mason Holgate replaced James Bailey and the suspended Jean-Yves Mvoto.
The Gills made one change to the starting 11 held 2-2 at Yeovil in their last outing. Jermaine McGlashan replaced Daniel Galibraith, who dropped to the bench.
Aaron Morris returned to the bench after recovering from a hamstring injury whilst Reds stopper Ross Turnball misses his third game in a row due to a back injury.
Gills captain Doug Loft was the first man booked for a professional foul on Conor Hourihane in the Barnsley half.
A good ball in from McGlashan split the visitors’ defence but Bradley Dack in judged offside.
Milan Lalkovic tried to catch Gills stopper Stuart Nelson sleeping as he struck a curling 25-yard effort but the former Brentford ‘keeper was up to the task as the Reds had the first shot on target.
The visitors began to control the tempo of the game, the ball fell to Josh Scowen just inside the penalty area but the 21-year-old sliced his effort wide of the target.
There was a chance for John O’Sullivan, who watched his 25-yard effort fly over the bar. Could have easily had played a through ball to Scowen who would have been one on one with Nelson.
Bradley Dack hit his free-kick wide of the target as he tried to caress the ball into the top right corner after Ben Pearson bought down the Gills striker.
McGlashan found Marquis with a lovely cross after he once again broke down the right and beat George Smith, Marquis’ header was blocked by Lewin Nyatanga.
In added first half time Gills lost possession in a great counter-attack by the Reds, Conor Hourihane’s cross-field ball found O’Sullivan who played Scowen in behind the defence. It was a great chance for the youngster to score his second in as many games but he lashed his shot wide.
GEORGE WARING put Barnsley ahead with a right-footer in the 56th minute.
Gills manager Justin Edinburgh brings on forward Luke Norris for defensive midfielder Jake Hessenthaler
McGlashan once again got in behind the Reds’ defence as the winger caught Smith sleeping but Manchester United loanee Pearson covered well and put the ball out for a throw-in.
Barnsley found it hard to get out of their own half as the home side continued to press with urgency as they looked to level proceedings.
Brave goalkeeping from Davies as the Reds’ man charged off his line once again before being clattered on the edge of the box by Marquis.
Pearson ran through the heart of the Gills defence before knocking the ball to the right for Lalkovic but Pearson fell to the ground as he landed awkwardly on his ankle.
The ball fell to Marquis, who cut inside to his right, the Millwill loanee powerfully fired his effort from outside the box over the crossbar.
Barnsley almost put the game to bed four minutes from time as O’Sullivan’s shot from the right hand side of the box was destined for the top corner, but a sublime finger-tipped save from Nelson denied the Blackburn Rovers man. It was O’Sullivan’s last contribution as he was replaced by James Bailey.
Great goalkeeping from Davies who produced a fine save with his legs from Gills man of the match McGlashan who was played in from Dack, the midfielder should have stolen a point for the home side.
Gillingham: Nelson (GK), Garmston, Egan, Ehmer, Loft (Capt), Hessenthaler, Marquis, McDonald, McGlashan, Dack, Hoyte. Subs:Martin, Legge, Morris, Galibraith, Morris, Norris, Romeo.
Barnsley: Davies (GK), Holgate, Cranie (Capt), Nyatanga, Smith, Lalkovic, Scowen, Pearson, Hourihane, O’Sullivan, Waring.Subs: Berry, Hemmings, Oates, Williams, Dibble, Bailey, Lita.
Referee: Kevin Johnson (Somerset).