The League One side, positioned 84 places beneath the Gunners in the English football pyramid, stunned Mikel Arteta’s team by taking the lead in the 21st minute.
Aaron Loupalo-Bi found the net for the hosts, leaving Arsenal with an unexpected challenge against their lower-league opponents.
Arsenal eventually restored parity after the interval, with Viktor Gyokeres finding the back of the net. However, despite creating several opportunities, the visitors could not find another goal to settle the contest during normal time.
Their task became even more difficult in the 86th minute when teenage midfielder Max Dowman received a red card for kicking out following a heavy challenge from Fleetwood’s Harrison Neal.
Goalkeeper Jay Lynch then proved instrumental in keeping the hosts in contention, producing crucial late saves to deny Ben White and Martin Odegaard.
His interventions ensured the tie proceeded to a penalty shootout, where Lynch continued his impressive performance by saving Bruno Guimaraes’ spot kick.
Conor Haughey subsequently converted the decisive penalty, sparking wild celebrations at Highbury Stadium. Fleetwood supporters poured onto the pitch as manager Matt Lawlor broke down in tears, overcome by the magnitude of his side’s achievement.
Fleetwood’s quarter-final opponents will be determined following Wednesday’s meeting between Chelsea and Liverpool, with the draw scheduled to take place after that fixture.
