Sharp-shooter Ricky Miller pegged the Gills back at Dover on Saturday.
Gillingham took an early lead through Brennan Dickenson but Miller levelled for the hosts.
The Gills fielded new signing Adedeji Oshilaja in their defence, having joined on loan from Cardiff City the day before.
Visiting boss Justin Edinburgh started with a 4-4-2 formation, as Oshilaja partnered Max Ehmer at the back.
It was the perfect start for the Gills as Dickenson netted his first of the summer, heading in Rory Donnelly’s cross from close-range, just two minutes into the match at Crabble.
The hosts were always a threat, with lively Miller and former Gills striker Stefan Payne posing plenty of problems for the League 1 side.
It was former Luton man Miller who levelled on 15 minutes, with a great chip over Glenn Morris, after the ball ran for him centrally. It was Miller’s fourth goal in five.
Dack, wearing the captain’s armband in the absence of Doug Loft, had an angled shot saved while Donnelly headed a chance into the side-netting.
Payne had one effort ruled out for a foul on Morris but moments later fired just wide from 20 yards, after attempting a lob over the keeper, after a ball bounced over the head of Ehmer. The Gills had earlier got away with a mistake at the back, when Bradley Garmston’s stray pass created a chance for Miller.
Oshilaja was replaced at the break by John Egan after a promising first 45 minutes, showing composure on the ball and strength in the air.
Dickenson had a busy afternoon for the Gills, playing upfront alongside Rory Donnelly, and he tried his luck twice early on in the second half. One effort went into the side-netting and another into the keeper’s hands.
Ryan Jackson had an angled shot saved and Dack also fired an effort into the arms of the goalkeeper. Miller volleyed a good chance over for the hosts.
A series of substitutions for both teams slowed the pace of the game down in the latter stages. Gills’ first year scholar Darren Oldaker, an attacking midfielder, was one of those to appear off the bench, having impressed recently for the development team.
A good save from Dover keeper Mitch Walker denied Dack from hitting a winner with six minutes left, blocking the close-range effort.
Dover Athletic: Walker, Magri, Sterling (Wynter 80mins), Grimes, Raggett, Orlu, Deverdics (Diallo 74mins), Bellamy, Payne (Ofori-Acheampong 76mins), Miller (Modeste 69mins), Murphy. Subs not used: Priddle, Nyaruwa, Rafferty, Burnett-Williams.
Gillingham: G Morris, Jackson, Garmston (Williamson 66mins), Ehmer, Oshilaja (Egan 46mins), A Morris (Osadebe 58mins), Hessenthaler (Oldaker 80mins), Houghton, Dack, B Dickenson, Donnelly (Norris 74mins). Subs not used: Nelson, List, M Dickenson.