Gillingham became the first League Two team in 26 years to reach the fourth round of the Carabao Cup when they beat Brentford on penalties after a 2-2 draw.
Ivan Toney opened the scoring in the third minute.
The Gills scored their first attempt of the game after 75 minutes as substitute Mandron headed in.
They recorded a stunning upset as Mikkel Damsgaard was the first to miss in a high-quality shoot out.
After reaching the last four in 2020-21, Thomas Frank said his side were in the competition to win it and he put together a strong line-up to welcome Toney back.
The Gills' late arrival at the stadium pushed the kick-off back by 20 minutes.
Two days before England's World Cup squad announcement, a long ball from David Raya set up Toney for a simple tap-in.
Despite their dominance, the Bees were not able to put the game beyond Neil Harris' visitors, who are 20th in the fourth tier.
They were punished when Alex MacDonald found fellow substitute Mandron with a cross with 15 minutes remaining and that single chance in open play proved enough to force penalties.
MacDonald held his nerve with the first sudden-death penalty after a series of well-taken spot-kicks, before Damsgaard missed to send Gillingham into the fourth round.
After being demoted from League One last season, Gillingham have had a hard time returning to the fourth tier.
Harris' side have only scored six goals so far this season, and have slipped to 22nd in the league.
At the Gtech Community Stadium, they only had one shot and seven of them were on target.
They were able to prevent their top-flight opposition from putting the game out of reach to set up their shootout triumph which sent them into the last 16 for just the second time in the club's history.
Despite fielding a strong starting line-up it is now one win in nine matches for the Bees, who face a trip to Manchester City on Saturday in their last game before the World Cup.
In his last chance to impress the England manager before he names his final World Cup squad on Thursday, Toney was able to make the scoresheet and offer a reminder of his spot- kick prowess.
Frank claimed that Toney had already done enough to be selected for the World Cup after he scored two goals in a 2-0 win over Seagulls.
Since that double took his tally to eight goals in 10 games, Toney has not scored in 270 minutes of football in the top flight.
Despite being called up to the England squad for the first time in September, Toney missed out on a chance to shine as he sat out the draw with Forest due to suspension.
Currently assisting the Football Association's enquiries into allegations of historic match betting, he was able to focus on achieving his childhood dream of representing England at the World Cup.
The early contribution was not enough to see the progress of the team.
All Rights Reserved © 2024
