Hornchurch booked their place in the fourth qualifying round of the FA Cup with a 3-0 win over Braintree Town.
But Romford bowed out after suffering a 5-0 home loss to Chelmsford City at Mayesbrook Park, while Billericay face a replay with Biggleswade Town after a 3-3 draw.
The Isthmian League Premier Division leading Urchins had avoided upsets against lower league outfits Ipswich Wanderers and Maldon & Tiptree in the previous rounds and welcomed their National League South rivals to Bridge Avenue boasting a six-game winning streak in all competitions.
Only 14 minutes had been played when Ola Ogunwamide put Mark Stimson's men in front and they doubled their advantage just past the half-hour mark through Liam Nash.
And that was how it stayed until five minutes from time when Nash netted his second and Hornchurch's third goal of the tie, to earn them another £5,625 in prize money and leave them just 90 minutes away from the first round proper.
Essex Senior League Romford had already beaten league rivals Saffron Walden Town and Takeley, Isthmian North side Hashtag United and Isthmian Premier outfit Potters Bar in this year's competition, picking up £8,194 in prize money, and faced Chelmsford City in front of a crowd of 336 at Barking.
Manager Steve Butterworth had claimed his understrength side - without the experienced duo of Scott Doe and Tambeson Eyong - faced 'mission impossible' against their higher-ranked rivals, but they held the visitors rivals at bay until 11 minutes into the second half, when Khale Da Costa finally broke the deadlock.
Adebola Oluwo quickly made it 2-0 on the hour mark, with Da Costa adding a third on 72 minutes.
George Allen was then given his marching orders six minutes later, reducing Boro to 10 men, and Da Costa completed his hat-trick from the penalty spot before Tom Blackwell completed City's nap hand six minutes from time.
Boro picked up another £1,875 in prize money and will now turn their focus onto their promotion bid and FA Vase campaign.
Billericay took the lead in front of 638 at New Lodge on 35 minutes through John Ufuah, but saw Biggleswade's Onyeagware level as the first half drew to a close.
Toby Stevenson restored the home side's lead before the break, though, and Bradley Stevenson made it 3-1 on 54 minutes.
And Blues looked set to progress until the closing stages, when Clements struck twice in the last 10 minutes to earn his side a second chance.
The two sides will meet again in midweek, with the draw for the fourth qualifying round taking place on Talksport on Monday afternoon.
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