Hornchurch saw their hopes of a place in the first round of the FA Cup shattered amid some controversy against Oxford City.
Urchins were leading thanks to a fine Jack Munns goal as the first half drew to a close, but then saw Tom Wraight sent off for a late tackle.
And National League South City levelled before the break, before adding three more goals against the 10 men in the second half to ensure their place in the hat for Monday's draw.
The opening exchanges were fairly even, with the visitors maybe shading possession, but Hornchurch were hit by an injury to Rickie Hayles, who was replaced by Kenny Clark on 12 minutes.
Jean-Baptiste Fischer then got to the byline on the right and crossed for Lewis Coyle, but he couldn't get his header on target under pressure from Nathan Bertram-Cooper.
Mickey Parcell picked up the first booking of the tie after catching Coyle late inside the City half, with Liam Nash curling the ball over the head of Sam Higgins and behind moments later in a moment of promise for the hosts.
Lewwis Spence sliced a 20-yard shot well wide of the mark on 20 minutes then played Wraight in on the left, but his cross found the side-netting.
Bertram-Cooper picked up the second yellow card for Hornchurch for a sliding tackle on former Charlton Athletic striker Josh Parker, but the visitors were then penalised for a foul when Josh Ashby hoisted the free-kick into the box.
Urchins were then up in arms when Ola Ogunwamide was caught late by Tom Harrison, who had his name taken by referee George Laflin.
And City keeper Ben Dudzinski spilled an inswinging right-wing corner from Wraight, under pressure from Sam Higgins, but a teammate was on hand to clear the danger.
The respite was brief, though, as Urchins took the lead on 35 minutes when Munns wriggled into space on the right side of the box and smashed his shot home.
Higgins tried a speculative effort moments later, from fully 30 yards, but dragged the ball wide, while Klaidi Lolos smashed well over Joe Wright's crossbar from just outside the box with five minutes left in the half and had another effort blocked by Clark.
Higgins got another sight of goal as normal time drew to a close, but lifted his shot too high, and Urchins were reduced to 10 men in stoppage time when Wraight lunged in on Fischer on the touchline and was shown a straight red card.
Worse was to follow just before the half-time whistle as the ball was played into the home box and Lolos saw his close-range effort deflected into the corner of the net.
Lolos had an early shot saved by Wright after the restart, but Spence then lifted a great chance over at the other end, after an initial Parcell effort had come back off the angle of crossbar and post.
And Wright pushed a low left-footed drive from Coyle beyond the far post before thwarting substitute Alfie Potter on the opposite side of the box when the resulting corner was only half-cleared by the home side.
City then broke quickly on the right as Potter played in Parker, whose deep cross found Lolos beyond the far post, but he could only fire into the side netting.
Wright dived to his right to smother a shot from Zac McEachran but, after Munns saw a shot blocked at the other end, he could do nothing to keep out Reece Fleet's well-struck drive from the edge of the box, when he was teed up by McEachran on 58 minutes.
Parker headed Potter's cross straight at Wright, but drew the Urchins keeper into conceding a penalty moments later, then picked himself up to fire the spot-kick into the corner of the net and make it 3-1.
That left Urchins with the proverbial mountain to climb, with David Smith sent on in place of Muldoon to bolster their attacking options.
But Fleet was close to a fourth for the visitors, sidefooting just past the post from the edge of the box, and Lolos fired into the side netting on another City counter-attack.
Rain lashed down as the tie drew to a close, with Spence picking up a yellow card for a mistimed tackle in midfield.
And City grabbed a fourth at the start of four minutes of injury time when Lolos saw a shot blocked, after being teed up by Fleet on a counter-attack, and Parker bundled home by the far post.
Munns talked his way into Laflin's little black book in the aftermath, with Higgins collecting the fifth yellow card for the hosts for a foul on Canice Carroll, which summed up Hornchurch's frustration on the day.
Hornchurch: Wright, Parcell, Wraight, Bertram-Cooper, Hayles, Munns, Muldoon (Smith 64), Spence, Ogunwamide (Sutton 46), Higgins, Nash. Unused subs: Stimson, Christou, Reid, Joseph.
Attendance: 825.
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