A 94th minute equaliser robbed the Gills of their 100% record but to be truthful Barnet probably deserved something from the game.
Jack Payne's 35-yard screamer had looked as if it may have been enough to win the game up until that point - a goal worthy of winning any game -but as it was the Gills ended the night fourth in the League Two table.
Yes it was disappointing to not win but the Gills do remain unbeaten having taken seven points from a possible nine and don't forget it took until the back end of September last season to reach that total.
Gillingham were forced into one change after Chris Whelpdale suffered a dead leg at Crewe, Curtis Weston, who took his place on Saturday, started. Changes on the bench saw Dennis Oli and Danny Jackman replace Weston and Stefan Payne.
Two familiar names in Lawrie Sanchez's squad were former loanee goalkeeper Dean Brill and left-back Jordan Parkes a trialist at Priestfield under Mark Stimson.
Presumably the Gills skipper Andy Frampton won the toss as the visitors swapped ends to kick up the Underhill slope in the first-half and were well backed by 1052 travelling supporters.
Gillingham's neat passing saw them open up the Bee's rearguard twice early on. A Joe Martin free-kick found Weston who cut inside but fired straight at Brill. Then the keeper had to dive at Weston's feet as he broke clear on the left.
The Gills took a deserved lead in the seventh minute, Charlie Lee's long throw wasn't dealt with in the middle and Danny Spiller was allowed to ghost in from the right to net from close range. His second goal in as many games.
Parkes was booked in the 10th minute for mouthing off to referee James Linington following a challenge on him by the Gills goalscorer.
A free-kick conceded by Frampton on Jason Price in the 16th minute almost proved costly but Ross Flitney kept out a decent curling effort from Mark Marshall at his left-hand post.
Danny Kedwell went close to adding a second in the 21st minute with a neat glancing back header from a Barry Fuller cross which dropped inches wide.
The referee stunned Barnet by giving a corner from which, taken by Spiller, Montrose had a point-blank header blocked on the line seemingly by a combination of Brill and Price.
The home side responded well though and made it a 'half of two halves', the Gills enjoying the opening while the Bees enjoyed the latter section.
As it was the Gills had Flitney to thank for keeping them ahead with rather bizarrely his next two saves denied Gillingham players putting through their own goal.
First a low Marshall cross was miscued by Kedwell straight at the former Barnet keeper and moments later a low Izale McLeod cross was inadvertently directed goal-wards by Matt Lawrence but Flitney was alert to push out and Lawrence was able to make a more accomplished clearance.
Eight minutes from the break the Bees went close again. A neat move involving Sam Deering saw McLeod fire goalwards from the edge of the area but Flitney held the rising effort above his head.
Despite having a share of the possession the Gills were struggling to create clear cut chances, in a rare break forward a great ball from Spiller just evaded Kedwell at the near post.
H/T: 0 - 0
The Gills got their composure back at the start of the second-half after being given the run around towards the end of the opening 45 minutes, the first real chance though was blazed over by Weston in the 55th minute.
A neat one-two involving Kedwell and Weston deserved a better finish than the midfielders effort that was way off target.
Against the run of play in the second period, Barnet levelled in the 61st minute. Flitney punched a Mark Byrne clearance out as far as substitute Tommy Fraser, he poked the ball back into the area first time and McLeod, scorer of a hat-trick at Priestfield last season, was on hand to place a header beyond Flitney from around six yards.
Three minutes later and the Gills under immense pressure almost conceded again, Price who had looked far from match sharp, saw a low shot strike Flitney's right-hand post and roll across the face of goal before being cleared.
Dennis Oli replaced Spiller in the 66th minute just before Lawrence picked up his third booking of the campaign for a foul on the marauding McLeod.
Price went close again when he turned near the bye-line to the left of the Gills goal but his low shot flew across the face of goal.
Completely out of the blue the Gills re-took the lead in the 74th minute. Lee broke forward and laid the ball off to Kedwell, he waited for Jack Payne who strolled on to his pass and thumped home a terrific strike from around 35 yards. His reward, to be substituted immediately with Danny Jackman going on.
Four minutes later and Price was given the opportunity to equalise but when Marshall set him up with a good cross the forward headed wide.
Not surprisingly Price was withdrawn shortly afterwards to a mixture of boo's and applause at the same time Matt Fish replaced Weston.
Barnet went in search of another equaliser but were far too hurried and didn't create a worthwhile effort on goal as the seconds ticked away with the Gills defending heroically once again.
That was until the final seconds when Danny Senda thumped a free-kick forward, Clovis Kamdjo rose highest and headed across goal to where the unmarked McLeod was able to smash home.
Attendance: 2466 (1052 Gillingham fans)
Barnet - Brill, Senda, Parkes, Hughes (Fraser H/T), Byrne, Deering (Holmes 82), Uddin, Marshall, Kamdjo, McLeod, Price (Taylor 79)
Unused subs - Geohaghon, O'Brien
Gillingham - Flitney, Fuller, Frampton, Lee, J Payne (Jackman 74), Kedwell, Weston (Fish 80), Martin, Lawrence, Spiller (Oli 66), Montrose
Unused subs - Richards, Gazzaniga