Fleetwood Town beat Arsenal 5-3 on penalties in the League Cup fourth round after playing out a 1-1 draw in normal time.
The Gunners became the first Premier League defending champions to be knocked out of the competition by a fourth-tier side.
The result was only the second time the north London side had been eliminated from the competition by a fourth-tier side, having lost to Bradford on penalties in the 2012/13 season.
Arsenal started the stronger side, but it was Fleetwood who broke the deadlock in the 21st minute.
Loupalo-Bi drove past teenage centre-back Marli Salmon before slotting the ball into the far corner.
Arsenal responded positively to going behind, but could not break down the hosts’ resolute defence.
Viktor Gyokeres restored parity in the 50th minute, scrambling the ball home from close range after Ceedach O’Neill’s delivery into the box.
Kai Havertz squandered a good chance to complete the turnaround. The ball fell kindly to the German, whose effort was blocked by Rhys Bennett.
Moments later, Havertz fluffed another opportunity, firing the ball into the side netting from a promising position.
Five minutes from the end, Dowman was sent off for unsporting behaviour. It was the first red card Arsenal received in the competition in five years.
Yet Mikel Arteta’s side created chances to score a late winner but were not clinical, sending the game to penalties.
Arsenal converted their first three spot-kicks, but Bruno Guimarães saw his effort saved by Jay Lynch. Fleetwood converted all five penalties to secure a 5-3 shootout victory and reach the EFL Cup quarter-finals for the first time.