Gicu Iordache and Corey Heath put the visitors two up in an explosive first five minutes but Andy Freeman pulled one back just before the break and then equalised on the hour mark. With the penalty shoot-out looming Rob Harvey scored from close range to condemn Chi to a second cup defeat in five days.
Miles Rutherford & Co made one change to the starting XI that had a real go against Tonbridge Angels mid-week in the FA Cup only to lose 2-1 to their National League South opponents. Ben Pashley moved across the back four to cover for Rob Hutchings and Corey Heath returned to the line-up with captain Connor Cody in the centre of the defence.
In Chi’s best opening to a game so far this season Lloyd Rowlatt skewed a shot wide with less than sixty seconds on the clock when a nice one-two between Pashley and Kaleem Haitham got the visitors down the left wing.
And then just three minutes in Iordache, who bagged a hat-trick a week ago in the league encounter with Haywards Heath, put Chichester in front after a break by Emmett Dunn on the right flank and a neat flick from Josh Clack.
A couple of minutes later Clack won Chi their first corner.
Brentwood struggled to clear Matt Axell’s delivery and both Scott Jones and Clack had follow-up shots blocked before the ball broke to Corey Heath who steered it past keeper Ollie Bowles for his first goal of the campaign.
Jones next forced a smart save out of Bowles as he latched on to a measured pass and moments later found Haitham only for the No11 to lift his effort high and wide.
A slick Chi move led to Bowles having to claim a Clack cross under pressure from Jones.
At the other end Wilberforce Ocran headed wide before a super hit by Rob Harvey fizzed inches past Steve Mowthorpe’s post.
Rowlatt, Iordache and Jones were then all involved in an attack that gave Bowles something to think about and his counterpart Mowthorpe was called into action as well getting down low to Ocran’s effort when Freeman played him in on 17 minutes.
The home side, shell-shocked in the first five, slowly started to get back into the match.
Dunn got his body in the way of a Harvey attempt and Mowthorpe brilliantly turned a shot by Sam Bantick round his post.
Jones almost got in at the mid-point only for Joe Heath to make a timely intervention before the Chi striker headed off target after good build-up play.
Harvey then picked out Bantick who wasted a good shooting opportunity seconds before Josh Gray also spurned another chance from a free-header.
Chi, who should have capitalised on their early goals still further, came at the hosts again when Rowlatt got Dunn in behind the defence to earn a corner.
The Canadian shot wide in the next attack after referee Graham Swanton ignored appeals for a set-piece after Iordache was brought down on the edge of the box.
Fans’ favourite Freeman pulled a goal back a couple of minutes before the break with a neat finish after the visitors failed to deal with a long ball upfield.
Bowles then denied Haitham with a fine fingertip save to claw the ball out for a corner that Axell took and Dunn got to only for a defender to clear his header away on the goal line.
Chichester struggled to create decent opportunities after the break but Iordache pulled a good stop out of Bowles early doors.
Brentwood won two corners back to back in the opening minutes.
Mowthorpe punched the second of these firmly away and did well to get a glove on Harvey’s effort following Freeman’s cross.
Devon Fender replaced Jones in the 53rd minute just before Bantick missed a golden opportunity to level as he arrived perfectly in the box to meet a lovely ball from Harvey but couldn’t get the right sort of connection.
And in a spell the hosts dominated skipper Rob Swaine’s downwards header at the back stick somehow bounced up and over the bar.
Cody almost caught Bowles out with a free-kick that nearly drifted over the keeper but he got an outstretched hand to the ball.
Swaine caused trouble at another corner with a header again in the 59th minute.
And then Freeman got the equaliser, with a goal that had been coming to be fair, after Chi failed to clear their lines.
Wyan Reid came on for Ocran and might have put his team ahead after a cross from the left flashed across the area and inches away from him at the far post.
Pashley then made a great tackle on Reid to turn the ball out for a corner that was headed over by Joe Heath.
Reid, Harvey and Gray linked up effectively but Harvey’s delivery was a little too high for Freeman.
Clack got Chi away on a rare attack only for Iordache to shoot straight at Bowles.
With 20 minutes go Prichard was brought on to replace Axell and the City youngster was soon involved winning the ball off Jake Gould and sending in a cross that was cleared.
Dunn next forced Bowles into a smart stop which gave the visitors a corner.
Reid cleared an effort off the line with nine minutes to go; Bowles gathered Pashley’s cross easily enough; and a Haitham attempt was deflected for another corner.
Cody broke up a nice move between Reid, Harvey and Gray and got Chi on the counter but Prichard couldn’t keep his shot down.
Then a defender headed away Haitham’s next effort.
Mowthorpe did well to chest a through ball back into his area and get hold of it with Harvey posing a threat.
Freeman had the ball in the back of the net in the last minute of normal time but an assistant’s flag for offside denied him and his side a third goal.
Substitute Robbie Rees won a set-piece on the edge of the Chi penalty box as the game moved into the third minute of additional time.
Rees picked himself and found fellow sub Jack Dickinson who couldn’t guide the ball past Mowthorpe from point-blank range as the visitors’ shot-stopper made an important save that looked to have sent the game straight to pens.
Harvey had other ideas however, steering home a cut-back from Freeman, with practically the last kick of the game, to give Brentwood an extraordinary comeback win.
Chi return to Isthmian South East action next on Saturday 24th October when they travel to Herne Bay.
Chichester – Mowthorpe, Dunn, Pashley, Axell, Cody, Heath, Clack, Rowlatt, Jones, Iordache, Haitham. Subs – (Bennetts, Prichard, Fender, Ender, Overton)