Martin Allen's Gillingham side stayed top of League Two with a win at bottom club Barnet on his return to Underhill.
Allen, who left the Bees in May, saw his side go ahead through Jack Payne's spectacular drive before Danny Kedwell nodded home to double their advantage.
Jack Saville managed to pull one back for the hosts when he headed home a corner from Mark Byrne.
But Deon Burton restored the visitors' two-goal advantage with a close-range header to complete the scoring.
Gillingham did have chances to increase their lead in the second half, but both Allen and Charlie Lee could not direct their headers on target.
Victory for the Gills means that they have continued their 100% away record so far this season.
The Bees, meanwhile, remain without a league win this campaign and are rooted to the foot of the table.
VIEW FROM THE DRESSING ROOM
Barnet manager Mark Robson told BBC London 94.9:
"I seem to be saying the same things, which is a bit disappointing. We conceded three goals today and all three were avoidable.
"Someone didn't track their runner, a man didn't mark his man in the box, and we didn't deal with a set-piece.
"We started the game well again and we looked like we were OK up until the goal. Then we conceded through our own fault and then you're 2-0 down.
"We were passing it around well, we created more opportunities but we have come out losing 3-1. It has got to change."
Gillingham manager Martin Allen told BBC Radio Kent:
"It was always going to be a tough game. It was a banana skin waiting to happen.
"Going 2-0 up so early didn't help us because complacency set in. Barnet have got match winners and I knew they were going to be a threat.
"We stood firm and the supporters gave good backing. There were over 1,000 supporters singing their hearts out and it's good to be a part of a good decent honest group of professional footballers."