Gillingham scored early on against top of the table Rotherham but finished well beaten with 10 men and picked up two more injuries.
Olly Lee scored for the Gills inside five minutes but Rotherham hit back with goals from Freddie Ladapo and Mickel Miller. Dan Barlaser scored one penalty and missed another before adding a fourth from open play as Gillingham played the last 20 minutes with 10 men following Ryan Jackson’s dismissal. A super strike from Chiedozie Ogbene finished off the scoring.
Gillingham had players back training this week following injuries but neither David Tutonda or Rhys Bennett were involved. First choice keeper Jamie Cumming was also absent due to Covid.
It meant the Gills were still desperately short of options, calling up second year youth player Tom Crump. He joined three 18-year-olds on the bench, with Gerald Sithole, Harvey Lintott and Bailey Akehurst the options for manager Steve Evans to make changes.
The home fans were on their feet to applaud Evans before kick off, grateful to his previous promotion success at the club, but it was the away supporters cheering early on.
Lee netted the opener for Gills on five minutes, Jackson supplying the cross after Stuart O’Keefe had done well to win them possession.
Chapman saved well from Michael Ihiekwe but things started to go downhill for the Gills.
Max Ehmer went off injured after just 10 minutes with what looked like another shoulder injury. It meant Lintott seeing action early on, slotting in at right wing-back as part of the five-man defensive unit.
The Gills were doing a decent job of holding Rotherham out but the visitors finally struck with 39 minutes gone. Robbie McKenzie slid in for a challenge as Chapman also came out to save from Michael Smith and the ball popped out for Ladapo to score from close range.
Worse followed on 45 minutes. Ihiekwe crept in unmarked at the back post to head the ball into the box, it was cleared to the edge of the area but from there Miller fired in through a crowded box, with the aid of a deflection to complete the turnaround.
Evans swapped it around upfront at the break, with teenager Gerald Sithole replacing injured John Akinde, while he changed the shape as well, reverting to four at the back.
Home striker Smith uncharacteristically put a couple of good chances wide in the early stages of the second half.
Rotherham got a third from the penalty spot, smashed down the middle by Barlaser, after McKenzie was penalised for holding onto Ihiekwe as a corner was played into the box.
Smith was keen to get in on the act, hitting another effort wide, while a rare chance for Gills fell to Danny Lloyd but he tried to find Sithole instead of going for goal himself and the ball was cleared.
Gillingham had to play the last 20 minutes with 10 men after Jackson picked up a second booking of the night - his first was for time wasting when they were 1-0 up - as he dragged winger Chiedozie Ogbene to the floor just inside the box. Gills did at least have some fortune as Barlaser went for power again but struck the crossbar.
Barlaser did manage to score the fourth, rifling home from open play with nine minutes remaining.
Wes Harding went close to scoring a fifth with a shot that went just wide as the Gills were unable to offer anything themselves going forward.
A fifth goal did come and it was a super strike, Ogbene finding the top corner from the edge of the box on a forgettable night for the Gills, who registered just the one shot in the match.
Rotherham: Johansson, Edmonds-Green, Ihiekwe, Harding, Ogbene, Barlaser, Rathbone, Wiles, Miller (Ferguson 64mins), Smith (Kayode 75mins), Ladapo (Grigg 79mins). Subs not used: Vickers, Mattock, Lindsay, Odoffin.
Gillingham: Chapman, Jackson, Lloyd, McKenzie, Ehmer (Lintott 10mins), Tucker, O’Keefe, Phillips (Akehurst 73mins), Lee, Carayol, Akinde (Sithole 46mins). Sub not used: Crump.
Referee: Ross Joyce
Attendance: 8,008 (164 away)