But while Grimsby's finishing in the amazing 6-5 midweek win over Burnley was clinical this time they just could not finish the Kent club off.
Some of Grimsby's football was excellent and belied a side second from bottom in the table.
It was only the brilliance of Gillingham keeper Jason Brown that kept the Mariners at bay, but with steadier finishing the home side should have put the game beyond the visitors.
Grimsby also had Middlesbrough centre-back Jason Gavin making his debut on loan and both new boys fitted in well.
In another change from the midweek line up skipper John McDermott made a welcome return after injury in what was a much improved Grimsby defence performance.
It was sparkling entertainment for the crowd and although Grimsby had the better of it with some super link up play particularly between Steve Kabba and Oster they could not get the goals that their play merited.
The crowd roared them on and when the breakthrough came 13 minutes from time it looked like being a decisive one.
Gillingham made two second-half substitutions and one of the replacements striker Tommy Johnson did very well to lay on the header for Saunders whose fierce effort gave Grimsby keeper Danny Coyne no chance.
It was a good point for Gillingham after their midweek home defeat by Wolves, but they will surely play better than this at Stamford Bridge next week when they visit Chelsea in a Worthington Cup third round tie.