Barnet had made the perfect start, breaking the deadlock after just 50 seconds.
Medy Elito picked up the ball from a throw in and was almost invited to shoot by the Maidstone defence, an invitation he duly took up, firing into the top right corner from the edge of the box.
Barnet looked to create more chances, Elito looking to double his tally for the evening, cutting back onto his right foot before clipping it over the keeper but just over the bar.
Powell had a free kick saved by Cousins midway through the first period in a game that soon settled down after a frantic start.
Just before the half time whistle, Maidstone led a counter from a Barnet free kick and it resulted in Justin Amaluzor being fouled in the penalty area by Dan Sweeney.
Blair Turgott stepped up but Mark Cousins guessed correctly and pulled off a good save to maintain the Bees advantage.
Just after the restart, Barnet’s 693 minute long run without conceding came to an end when former Bee Amaluzor finished at the far post.
In a half of few chances, Maidstone took the lead when Rob Swaine lost his marker from a Powell free kick and headed past Cousins.
With less than 10 minutes to go, Antonis Vasiliou came on for his senior debut and became the latest in a long line of BFC Academy talents to be given a chance in the first team.
Soon after stepping on, he teed up fellow substitute Simeon Akinola who angled a shot looking for the bottom corner but it went agonisingly wide of the mark.
Maidstone would hold on for all three points and end Barnet’s 8-match unbeaten streak.
BARNET – Cousins, Alexander, Reynolds, Robson, Coulthirst, H. Taylor, Fonguck (Akinola 66), Elito (Barham 73), Tutonda, Sweeney, Mason-Clark (Vasiliou 83)
UNUSED – Matrevics, Charles
Attendance – 1,471 (129 Barnet)