The first chance of the game went to Grays as a cross from the right found Joao Carlos
unmarked in the centre of goal six yards out but his weak header was easily saved by Tom Lovelock.
A minute later another chance fell to the away side as a poor kick from the edge of his box by Lovelock went straight to Kenny Beaney
but his snap shot from the half way line went narrowly of the bar with the keeper stranded.
Grays did take the lead shortly after the half hour mark as the ball was worked into the Concord area. With his initial shot blocked, Brian Moses
showed great ingenuity to loop the ball over Lovelock from a narrow angle with his knee, the ball nestling in the far corner of the net, giving Moses his first senior goal for the club.
Concord’s best chance of the half came in the 40th minute as a cross from the left caused a scramble in the box before the ball broke to Danny Spendlove ten yards out but his shot went narrowly over the bar.
The home side started the second half on the front foot and put Grays under pressure early on.
In the 47th minute, Spendlove found space on the edge of the Grays box to fire towards goal. The ball looked to be heading for the bottom corner, but Lamar Johnson
was on hand to push the ball round the post.
Having made two substitutions at half time, one of them the introduction of top scorer Tony Stokes, Concord looked more dangerous as the game went on, but a head injury to James White in the 64th minute seemed to halt the home sides momentum as the games was stopped for seven minutes.
It was not until the final five minutes of normal time that it seemed to dawn on the Concord players they were about to be knocked out of the cup.
In the 85th minute, a vicious strike by Spendlove was well saved by Johnson to keep the away side in front.
A minute later, Tony Stokes found space down the left hand side of the area and his low shot went across the face of goal and narrowly passed the far post.
Grays made a late substitution, replacing Jared Small
with Daniel Subuola
In the 4th minute of injury time, Concord again came close as Stokes worked his way into the area on the left hand side before firing low towards the far corner, only to see his shot rebound off the post and bounce away to safety.
Just as the Grays defence looked to finally be breached, the game was settled with a second goal for the away side.
An incisive break away down the left hand side by Joao Carlos
stretched the Concord defence. The ball into the box was flicked on by Brian Moses
to Danny Bunce
at the back post. He controlled the ball before wrong-footing Danny Glozier and firing right footed into the far corner to the delight of the travelling fans.
Grays aw out the remaining six minutes of injury time with little fuss to book their place in the final where they will face one of Hornchurch, Southend or Waltham Abbey.
Grays Athletic: Lamar Johnson
, Craig Pope
, Junior Baker
, Ryan Kirby
, Lee Flynn
, Danny Bunce
, Kenny Beaney
, Leon Lalite
, Joao Carlos
, Jared Small
88), Brian Moses
Unused Subs: John Docker
, Dan Fry
, Joe Sweeney
, Jack West