Match ends, Sheffield Wednesday 3, Arsenal 0.
Sheffield Wednesday stunned a lacklustre Arsenal to reach the quarter-finals of the League Cup.
Wednesday took the lead when Ross Wallace fired in coolly from 18 yards.
Wallace created Lucas Joao's headed second and Sam Hutchinson turned home a third from four yards after the break.
Arsenal, who made nine changes to the team that beat Everton on Saturday and lost Theo Walcott and Alex Oxlade-Chamberlain to injury in the first 20 minutes, managed two shots on target.
After falling behind, the Premier League side never looked like getting back into the tie and Wednesday, conquerors of Newcastle in the last round, reach the last eight of the League Cup for the first time in 13 years.
Incredible Tuesday for Wednesday
Despite his side's eight-game unbeaten run, Wednesday manager Carlos Carvalhal said the Owls had just a "10% chance of progress".
The reality made his estimate look inaccurate to say the least, as just one effort of meaning from Per Mertesacker - tipped over by Joseph Wildsmith - threatened the home goal all night.
Wednesday owner Dejphon Chansiri wants the club in the Premier League by 2017 and on this evidence they could hold their own in the top flight.
"I am very happy about the players and for the club, it is an important victory for the club," said Carvalhal. "It was a full stadium, with a new generation of fans. We deserved what we got."
Wenger's nine changes - including full debuts for Glen Kamara and Alex Iwobi - possibly led to a lack of fluency and after sitting deep early on, Wednesday landed the perfect counter-punch when Wallace smartly passed home Daniel Pudil's cut-back.
Joao's header from Wallace's cross and Hutchinson's tap in sparked chaotic celebrations from the majority of the 35,065 inside Hillsborough, while Wenger was left contemplating two examples of poor set-piece defending by his makeshift side.
Wenger counting the cost
Wenger may also bemoan his luck after seeing Oxlade-Chamberlain limp off inside five minutes, only for his replacement Walcott to exit 13 minutes later with a calf problem.
Both players wore frustrated looks as they left the field and Wenger, who has not won at Hillsborough in 19 years, was left with few options to change the flow of the game at half-time having used replacements so early on.
His latest casualties - added to Mikel Arteta, Jack Wilshere, Danny Welbeck, Aaron Ramsey, Tomas Rosicky and David Ospina - mean Arsenal go in to fixtures against Swansea, Bayern Munich and Tottenham with a stretched squad.
The Frenchman will hope this humbling defeat does not curtail the momentum built with impressive wins over Manchester United, Bayern Munich and Everton in recent weeks but his side were blunt on the night, doing little with 71% of possession.
In truth, the margin could have been greater as Joao headed wide when unmarked before being replaced to a standing ovation with five minutes remaining.
Man of the match
Wednesday - ninth in the Championship - have two home games, firstly against mid-table Nottingham Forest before current leaders Brighton make the trip to Hillsborough.
Arsenal will be on the road for a huge four days in their season as they visit Swansea City on Saturday ahead of Bayern Munich in a crucial Champions League group game.
- 5LoovensBooked at 59mins
- 4HutchinsonBooked at 30minsSubstituted forMcGuganat 80'minutes
- 33WallaceBooked at 45mins
- 41BannanSubstituted forSemedoat 75'minutes
- 18Lucas JoãoSubstituted forNuhiuat 85'minutes
- 2DebuchyBooked at 59mins
- 47KamaraSubstituted forBielikat 60'minutes
- 28CampbellBooked at 86mins
- 15Oxlade-ChamberlainSubstituted forWalcottat 5'minutesSubstituted forBennacerat 19'minutes
- Graham Scott
- Shots on Target
Second Half ends, Sheffield Wednesday 3, Arsenal 0.
Attempt missed. Joel Campbell (Arsenal) left footed shot from the right side of the box misses to the left. Assisted by Kieran Gibbs with a cross following a corner.
Corner, Arsenal. Conceded by Joe Wildsmith.
Joel Campbell (Arsenal) wins a free kick on the right wing.
Foul by Daniel Pudil (Sheffield Wednesday).
Joel Campbell (Arsenal) is shown the yellow card for a bad foul.
Foul by Joel Campbell (Arsenal).
Daniel Pudil (Sheffield Wednesday) wins a free kick in the attacking half.
Substitution, Sheffield Wednesday. Atdhe Nuhiu replaces Lucas João.
Attempt missed. Lewis McGugan (Sheffield Wednesday) right footed shot from the left side of the box misses to the right. Assisted by Daniel Pudil.
Substitution, Sheffield Wednesday. Lewis McGugan replaces Sam Hutchinson because of an injury.
Delay over. They are ready to continue.
Delay in match Sam Hutchinson (Sheffield Wednesday) because of an injury.
Substitution, Sheffield Wednesday. Josè Semedo replaces Barry Bannan.
Mathieu Flamini (Arsenal) wins a free kick in the defensive half.
Foul by Jeremy Helan (Sheffield Wednesday).
Foul by Mathieu Flamini (Arsenal).
Barry Bannan (Sheffield Wednesday) wins a free kick in the defensive half.
Corner, Arsenal. Conceded by Daniel Pudil.