Overview
- Fourth-division Grimsby advanced 12-11 on penalties at Blundell Park after a 2-2 draw in the second round.
- Charles Vernam and Tyrell Warren put the hosts 2-0 up in the first half, with André Onana at fault on the second goal.
- Bryan Mbeumo pulled one back on 75 minutes and Harry Maguire leveled in the 89th to force spot-kicks.
- The shootout reached 26 attempts and ended when Mbeumo struck the crossbar, prompting a pitch invasion by home supporters.
- United fielded numerous regulars, with costly signings Matheus Cunha and Mbeumo failing in the decider, intensifying scrutiny of recruitment and the manager.