A calamitous first half saw the Clarets enter the break three goals behind and the damage was too severe to overcome as City's impressive away form was brought to a sharp halt.
Jack Midson gave the hosts the lead as he lapped up a defensive mistake inside the opening ten minutes. Alex Wall doubled the Beachboys’ lead before Liam Nash extended their lead.
The Clarets started brightly but were unable to break the deadlock. Chris Whelpale came closest as he directed a header towards goal, but former Claret Sam Beasant produced a strong hand to tip it over the crossbar.
Despite the bright start, it was the hosts who took the lead first. City failed to deal with a long throw-in from Danny Green, the deep delivery bounced inside the Chelmsford box and player-coach Midson appeared at the far post to stab the ball home past Nathan McDonald.
The Beachboys could have furthered their lead four minutes as Scott Fenwick was penalised for a handball inside the area, but McDonald dived to his right to deny Midson a second goal.
Having had a bright start to the first half, Concord dominated proceedings after taking the lead.
Another defensive mishap handed the hosts another chance to score, although Joe Anderson acrobatically cleared the danger.
But it was not long before Concord added to their goal tally. A quick counter attack on 21 minutes beat the static Clarets and Wall headed Green’s cross past McDonald.
Two minutes later the hosts scored a third. The hosts direct style of play troubled City, Anderson was beaten just inside his own area and McDonald could not match Nash’s low strike.
With their confidence completely beaten, the Clarets almost conceded a fourth before the break. Michael Spillane failed to control the ball under pressure from Wall, but the Concord striker could only watch as McDonald saved his powerful shot.
Whelpdale went in search of a consolation goal but his low effort was an easy save for Beasant right before half-time.
If the Clarets were to have any chance of providing an almighty comeback then an early goal was certainly needed. City almost had that early goal as Fenwick flashed a cross into the box, while Spillane and Anthony Church both had good chances blocked on the goal-line.
City boss Rod Stringer opted to make two changes in quick succession as he looked to pull a goal back. Having signed earlier today, Chez Isaac and Ruel Sotriou came on in the place of Amos Nasha and Jazzi Barnum-Bobb before the hour-mark.
Concord’s star man Wall was forced off through injury as he felt his hamstring, with Ahmed Abdulla replacing him with twenty minutes to go.
The Beachboys could have scored a fourth midway through the second half as McDonald and Spillane failed to deal with a loose ball. Nash almost tucked his way past the City ‘keeper but Khinda-John did well to make a tackle.
City’s last sign of any threat came with fifteen minutes to go. Whelpdale’s deep cross picked out Giles at the far post, the substitute played the ball back across to Church but the City skipper was unable to poke the ball home at the far post as City were left thoroughly disappointed in Canvey Island.