An unfortunate own goal from Ross Fitzsimons in the ninth minute set the tone for a dismal first half for City who fell further behind when Chris Bush conceded a penalty for a foul on Luke Wanadio.
Dartford skipper Elliot Bradbrook dispatched the spot kick with ease before effectively putting the tie to bed five minutes later when his shot on the turn bounced over the line off the underside of the crossbar.
The Clarets never really looked like threatening Dartford’s dominance until Robbie Willmott was brought on in the 66th minute and within four minutes City had scored twice with two Willmott crosses being headed in by Shamir Mullings.
Chelmsford threw the kitchen sink at Dartford in search of an equaliser but they weren’t able to force a replay with tempers flaring at the end of the match resulting in Adam Bailey-Dennis being given a straight red card in stoppage time.
Clarets boss Rod Stringer made four changes to his side from Monday night’s draw with East Thurrock with Corby Moore, Adam Bailey-Dennis, Phil Walsh and Shaun Jeffers coming in.
Stringer made his intentions clear pre-match saying that the league was his priority over the cup but ultimately there was a game to win and City started off brightly with Billy Bricknell forcing a smart one-handed save from Deren Ibrahim early on.
The Clarets early brightness though was dimmed when the Darts took an early lead with a bit of fortune. A cross from the right was headed against the post by Danny Harris, bouncing away from goal before dribbling over the line off the back of Ross Fitzsimons for an own goal.
Chelmsford were rattled and were fortunate not to be 2-0 down midway through the half as Dartford appeared to have scored a second goal.
A corner from the Dartford right was headed in from close range by Elliot Bradbrook but unbeknown to most in the ground referee Robert Massey-Ellis had ruled the goal out for a foul much to the bemusement of the away fans.
Chelmsford were really struggling to carve out any clear openings and were frustrating the home fans with their poor crossing from open play and from corners which were being easily fended off by Tony Burman’s side.
The Clarets did have a goal ruled out after bundling the ball in from a free kick but the linesman’s flag was up nice and early ruling it out and the fans’ mood was made even worse when Chris Bush gave away a penalty for a dubious looking foul on Luke Wanadio.
The decision looked soft but the referee pointed to the spot and Bradbrook dispatched it with ease with Fitzsimons rooted to the spot as the visitors doubled their advantage.
Before the half was out though Dartford more or less had one foot in the next round as they extended their lead through Bradbrook. A cross from the left hand side found the Darts captain who on the turn saw his shot come off the underside of the bar and over the line to make it 3-0.
Chelmsford were going to need the most monumental of FA Cup comebacks if they were to do anything in this competition and they had a good chance late in the half to get one back before the interval when Shaun Jeffers was picked out by a punt into the box but his effort lacked power to trouble Ibrahim.
Stringer made a change at half time with top scorer Shamir Mullings coming on for the misfiring Luke Daley and he was almost on the end of good build up play by Graham whose floated cross to the far post was just about cleared away by the visitors.
Graham was proving a nuisance down the left and he got another cross in that almost fell to Mullings before Ashley Miller followed up with a low drive that was well blocked by the Dartford defence.
Going into the final half hour the Clarets desperately needed a goal if they had any chance of getting back into the tie and they were thrust right back into the tie with two goals in two minutes, and it was the combination of Robbie Willmott and Mullings that struck again.
Having only been brought on a couple of minutes before Willmott hit a flat cross into the box which Mullings rose highest to head the Clarets back in the game.
City with their tails up went straight back on the attack and won a corner on the right hand side through Jeffers. Willmott crossed the ball in once again finding the head of Mullings who scored two in two minutes to put City right back into the tie.
Dartford were now hanging on for dear life as Chelmsford piled forward in search of an equaliser with cross after cross making its way into the Dartford penalty area.
City came close to levelling with a long range strike from Jeffers whose left footed effort from 25 yards out had to be smartly pushed wide by the diving Ibrahim.
Dartford naturally tried to slow the play down at every opportunity but the Clarets kept pressing looking to for one final clear cut chance to force a replay and they had two fall to them in a matter of seconds.
Mullings came within millimetres of a hat trick as his shot from distance was tipped onto the post by Ibrahim. The ball bounced back off the goalkeeper and into the path of Jeffers who somehow hit the underside of the cross bar as Dartford survived.
In the sixth minute of injury time tempers began the flare between the two sets of players after an apparent stamp by Adam Bailey-Dennis saw him shown a straight red card as Dartford scraped through to the next round at the expense of Chelmsford.
1. Ross Fitzsimons
2. Ashley Miller
3. Chris Bush
4. Corby Moore
5. Adam Bailey-Dennis
6. Phil Walsh
7. Luke Daley
8. Anthony Church
9. Shaun Jeffers
10. Billy Bricknell (C)
11. Bagasan Graham
12. Daniel Blanchett
14. Mark Haines
15. Shamir Mullings (On for Luke Daley 46’)
16. Josh Rees (On for Billy Bricknell 60’)
18. Jake Reid
19. Frankie Merrifield
20. Robbie Willmott (On for Phil Walsh 66’)
1. Deren Ibrahim
2. Tom Gardiner
3. Tom Wynter
4. Tom Bonner
5. Keaton Wood
6. Alex Brown
7. Ryan Hayes
8. Elliot Bradbrook
9. Duane Ofori-Acheampong
10. Danny Harris
11. Luke Wanadio
12. Andy Pugh (On for Luke Wanadio 85’)
14. Lee Noble (On for Ryan Hayes 75’)
15. Ellis Brown
16. Ben Francis
17. Tony Coxall
18. Ronnie Vint
Chelmsford City: Shamir Mullings 68’, 70’
Dartford: Ross Fitzsimons OG 9’, Elliot Bradbrook (p)32’, 37’
Chelmsford City: Chris Bush (Dissent – 28’), Bagasan Graham (Foul – 49’)
Dartford: Tom Wynter (Obstruction – 26’)
[b]Chelmsford City: Adam Bailey-Dennis 90+6’
Referee: Robert Masseyy-Ellis
Assistant Referees: Anthony Pope & Lee Grimsey
City Man of the Match: Bagasan Graham