Romford saw their FA Cup journey end early this year after a 3-1 home defeat against Welwyn Garden City.
And there were preliminary round exits for Essex Senior League rivals Athletic Newham and Barking, but Woodford Town earned a replay after netting two late goals in a 2-2 draw against Isthmian North side Bowers & Pitsea.
Boro had enjoyed a great run last season, before losing in the third qualfying round to National League South side Chelmsford City, and went into their clash unbeaten in six matches in all competitions this season.
But they found themselves behind after just four minutes as Dernell Wynter put the Citizens in front and were reduced to 10 men moments later as Darren Phillips was dismissed.
Bailey Stevenson doubled the Welwyn lead on 44 minutes, but Charlie Morris hit back from the penalty spot before half-time to give the hosts some hope.
And the tie remained in the balance until the closing stages, when Lucas Jordan made it 3-1 on 83 minutes.
Woodford travelled to the Len Salmon Stadium also unbeaten in six matches this season and having welcomed Jaedon Phillips back into their ranks on Friday.
But they fell behind on 35 minutes as Lewis Chambers netted and were left up against it when Jack Thompson made it 2-0 just past the hour mark.
Shane Baptiste’s men halved the deficit in the first minute of injury time through George Thompson and snatched a share of the spoils with virtually the last kick of the match thanks to Kahlil Kirwan-Meade to ensure a second meeting at Ashtons.
Barking lost 2-0 at Isthmian North side Heybridge Swifts, with Athletic Newham beaten 3-0 at home by Westfield.
Brentwood booked their place in the next round with a 2-1 win over Kings Langley, thanks to a last-minute winner from Sam Deering.
Jack Adlington’s 26th-minute opener was cancelled out by Rene Howe five minutes from time, but Deering had the last word in front of a crowd of 280.
AND ITS SAM DEERING AT THE DEATH!!!
Lobs the Kings Langley keeper from inside the box!!!
Minutes left here! Come on you Blues! pic.twitter.com/SlFI1SM26H
— Brentwood Town F.C. (@BrentwoodTownFC) August 19, 2023
Isthmian North rivals Enfield bowed out after a 1-0 loss at Leighton Town, with the only goal of the game coming nine minutes before half-time in front of a crowd of 429.
Hutton returned to the top of the Thurlow Nunn League Division One South table with a 2-0 home win over Hackney Wick at Billericay Town’s New Lodge.
And Newbury Forest celebrated their second win of the season, after beating Wormley Rovers by a single goal at Oakside Stadium.
But Barkingside fell to a 2-0 defeat at Benfleet and Enfield Borough went down by the same margin at home against Basildon Town.
Tower Hamlets saw their home fixture with Hoddesdon at Mile End Stadium postponed.
Referee has called the game off to the surprise of both teams.
Reasoning – Geese Poo on the pitch.
Both teams worked together to clear whatever was left on the pitch. But referee was not interested. Laughable really pic.twitter.com/CTCl5B7SkK
— Tower Hamlets FC (@TowerHamletsFC) August 19, 2023