Goalkeeper Callum Thurnham was the hero for Coedpoeth as he saved three kicks in a penalty shoot-out to ensure his team pulled off the shock of the round.
The side currently bottom of the North East Wales League Premier Division pulled off a surprise cup win over the leaders on Saturday.
Coedpoeth prevailed 3-1 on penalties over a much-fancied Corwen after the game itself finished 0-0.
Both teams have played nine league matches this season, but there are 23 points between them. That counted for nothing at the weekend.
Corwen had plenty of goal attempts in the first half, but failed to score from any of them.
Alex Webster floated a free kick into the United box, where Dylan Davies sent his shot narrowly wide.
Robbie Williams drove a free kick straight at Coedpoeth number one Thurnham, who then tipped over a Dafydd Evans strike.
At the opposite end, Oliver Lewis’ free kick went up and over the wall, hit the crossbar and bounced away from goal.
Williams and Thomas Lloyd fired off target for Corwen before the break.
Chances came at both ends after the turnaround, Corwen’s shooting again not quite at its sharpest.
In stoppage time the visitors looked to prevent a penalty shootout, as Adam House went around Thurnham and sent a low shot at goal, which was blocked by a defender.
The final whistle meant the game was to be decided by penalty kicks and Corwen were hoping to make it third time lucky after two previous shootout defeats this season.
Adam Lloyd, Michael Taylor and Kady Seabrook converted for Coedy, but keeper Thurnham emerged the hero for the hosts as he saved kicks from Webster, Henry Evans and a cracker to deny Tom Mann.
The win sees Coedpoeth progress to a home quarter-final against Greenfield.
Harry Roberts and Scott Nelson bagged the goals which sent Caerwys through to the Mike Beech Memorial Trophy quarter-finals.
Roberts netted on 27 minutes and Nelson 57, Mark Williams replying for the visitors after 68.
Mikey Latham was back to his usual deadly self as he notched a hat-trick in the sinking of Championship visitors Overton.
Latham struck on 32, 73 and 78 minutes, while there were also goals from Jake Harper and Sean Price.
Ben Duffy fired Rhostyllen in front on 14 minutes, but Ryan Price Jones equalised after 44.
There were no further goals, so it went to penalties and Greenfield edged it 5-4.
Harry Lambert and Samuel Wainwright pocketed the crucial goals which made sure Mynydd Isa progressed to the last eight, Sam Giles replying.
Jack Pyke-Jones (2), Edward Brown, Gareth Higgins, Ben Hughes and Liam Hughes split the goals as dominant Penyffordd rattled up a half-dozen.
CPD Gronant v Plas Madoc
Lex XI v Johnstown
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Josh Bachner put Brymbo well on their way to a third win of the season as he produced a hat-trick inside the first seven minutes.
Bradley Reid (2, 1 pen), Sam Wall, Joshua Price, Jordan Reid and Josh Gunwhy supplied the remainder of the Steelmen’s nine.
Nathan Taylor and James Greenshields responded for the hosts.
A narrow win on the road for United, Rhys Powell (2) and Jack Swinnerton their marksman, Callum Powell with a pair for Johnstown.
Joe Mitchell was a four-goal star for Sychdyn, Kieran Jones (2), Daniel Mountstephen and Jordan Walker with the rest.
Although Liam Mortimer gave Yr Wyddgrug a 12th minute lead, Aston hit back to win with two goals inside a minute from Ryan Edge after 27 and 28.
Matthew Holmes and Lewis Dallimore bagged a brace apiece for the visitors, Alyn Roberts adding a late penalty, while Nicholas McCormick scooped a home team consolation.
Greenfield were too strong for their hosts, Dylan Pugh, Ryan Jones (2), Dion Davies and Jacob Jones rattling up a five-goal salvo.
Kobie Betts and George Walshaw Davies scored one apiece for victorious hosts Mynydd Isa Reserves.
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