London - Second-tier Sheffield Wednesday stunned Arsenal 3-0 at Hillsborough to send the Premier League contenders crashing out of the Capital One Cup.
Arsene Wenger's sidel were well beaten by Championship side Wednesday and also lost Alex Oxlade-Chamberlain and Theo Walcott to injury in the first half.
Ross Wallace put Wednesday ahead after 27 minutes and then teed up Lucas Joao for the hosts' second goal shortly before half-time, with Sam Hutchinson completing victory early in the second period.
Wenger, who has never won the League Cup, had made eight changes to the team that beat Everton 2-1 on Saturday for the game, which was a repeat of the 1993 final.
Asked how his young fringe players had handled the occasion, he delivered a scathing assessment, telling Sky Sports: "It was too high for them. They are not ready to play at this level, none of them."
On the injuries to Oxlade-Chamberlain and his replacement Walcott, both of whom limped off inside 18 minutes, he added: "It is a big blow for us, of course to lose the game, but even more for the other competitions, which are very important for us, to lose two players of that stature."
It was Wednesday's second Premier League scalp in this season's competition, following their third-round win at Newcastle United, and brought Arsenal's run of four successive victories to an end.
"Everything belongs to the players. They were fantastic," said Wednesday's Portuguese manager Carlos Carvalhal.
"We put a plan together and they did it 100 percent."
Elsewhere, second-tier Hull City defeated in-form Premier League side Leicester City 5-4 on penalties after a 1-1 draw, while Everton also needed penalties to beat Norwich City, 4-3, following another 1-1 draw.