Hornchurch produced yet another upset to beat Darlington book a place in the semi-finals of the FA Trophy for the first time in club history.
Having already knocked out Dulwich Hamlet, King's Lynn Town and Maidstone United on their run to the last eight, Mark Stimson's men saw off the National League North Quakers in the North East.
The Quakers had not played in National League North since January 12, when they lost 1-0 at Farsley Celtic, which left them in 19th place with 13 points from 11 games before the decision to null and void the season.
But they had beaten National League outfit Wealdstone 4-1 in the last 16 three weeks ago, when Hornchurch were on their way to a thrilling 5-4 last-gasp success over Maidstone United at Bridge Avenue.
Barely two minutes had been played when Erico Sousa collected the ball on the left, beat his man and fired just wide of the near post for the hosts, and the same player was off-target with another attempt moments later.
But Urchins got their first sight of goal on nine minutes when Sam Higgins sent a volley just wide of the upright, and Ellis Brown then flashed another effort just over from the edge of the box after a good move.
Adam Campbell fired wide for Darlington on 13 minutes, but Liam Nash forced Sol Brynn into his first save of the tie with a 20-yard shot.
Play was held up briefly while Michael Liddle received treatment for a cut and the Quakers had a great chance to open the scoring on 24 minutes when Daniel Maguire lifted the ball over Joe Wright and the crossbar.
But Urchins broke the deadlock two minutes later when Nash - the matchwinner against Maidstone – found the net once again, sidefooting home after a fine run to the byline and pull back from Remi Sutton.
Campbell dragged a shot just wide of Wright’s goal as the home side looked to respond, with the Urchins keeper getting down well to save from Maguire and then pushing out an attempt from Sousa five minutes before the break.
But it was all square in stoppage times as Campbell released Sousa and he made no mistake, firing into the far corner of Wright’s net.
Ronnie Winn made way for Nathan Cooper during the interval and Urchins were back in front before the hour when Nash was fouled in the box and Higgins converted the penalty.
Wright saved well from Sousa just past the hour mark as Darlington pressed and Josef Wheatley fired wide after a scramble in the Hornchurch box.
Charlie Ruff was booked on 64 minutes and made way for Chris Dickson soon after as boss Mark Stimson made his second change of the tie.
Wheatley was denied by Wright, before Maguire was similarly thwarted and Sousa fired a great chance straight at the Hornchurch keeper on 79 minutes.
Dickson fired over at the other end three minutes later, before Higgins made way for the fresh legs of Charlie Stimson and the home side were reduced to 10 men with five minutes remaining when Will Hatfield was given his marching orders for a second bookable offence.
And Urchins survived five minutes of stoppage time to claim an historic win to leave themselves just 90 minutes away from a trip to Wembley Stadium.
Hornchurch: Wright, Sutton, Muldoon, Hayles, Clark, Brown, Spence, Higgins (Stimson 83), Nash, Winn (Cooper 46), Ruff (Dickson 67).
Unused subs: Bentley, Hassan, Cummings, Thackway.
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