Welbeck on target in victory
Danny Welbeck opened his Arsenal account as the Gunners blew Aston Villa away with an astonishing triple blast.
A brilliant first-half spell from the visitors saw Mesut Ozil open the scoring before Welbeck struck and Aly Cissokho's own goal made it 3-0.
The goals came in three minutes and 15 seconds to end Villa's promising early threat.
The hosts would have gone top of the Barclays Premier League with a win b ut despite a bright start they were carved apart as they slipped to their first defeat of the season, in front of watching chairman Randy Lerner - his first home game for almost two years.
Ashley Westwood pulled out of the Villa squad during the warm-up with a virus and was replaced by Carlos Sanchez, with Joe Cole added to the bench.
Ciaran Clark also replaced Nathan Baker from the 1-0 win at Liverpool to partner Philippe Senderos.
Ron Vlaar failed to shrug off a calf injury which kept him out of the Anfield victory, with Jores Okore included on the bench.
Arsenal made three changes from their 2-0 Champions League defeat to Borussia Dortmund as Alex Oxlade-Chamberlain, Santi Cazorla and Calum Chambers came in.
Out went Jack Wilshere, Hector Bellerin and Alexis Sanchez - despite the Chilean initially being named on the team sheet.
And Villa took advantage of Arsenal's overall indecisiveness as they made a strong start.
Fabian Delph forced Wojciech Szczesny into a low save after just two minutes following the goalkeeper's poor clearance.
Welbeck fired over in response but Arsenal were given little time to settle by a vibrant Villa side.
Alan Hutton nodded over on 17 minutes as Villa continued to carve out the best chances - and they should have taken the lead five minutes later.
Chambers was booked for bringing down Gabby Agbonlahor and Clark met Tom Cleverley's delivery at the far post, only to be denied by a point-blank save from Szczesny.
But the Gunners stunned Villa with three quickfire goals to win the game.
The hosts had been edging the contest but collapsed suddenly, starting when Welbeck teed up Ozil to run through and coolly roll past Brad Guzan for his first goal of the season on 32 minutes.
Then the World Cup winner repaid the favour when he crossed from the left and Welbeck smashed in from four yards.
Villa were shell-shocked and they were bypassed again on 36 minutes when Kieran Gibbs' cross was turned in by the sliding Cissokho.
Aaron Ramsey then shot wide with Villa dazed.
While the half-time scoreline was harsh on the hosts, the Gunners had taken control and Guzan claimed Welbeck's effort soon after the break.
Clark had a chance to haul Villa back into the game on 57 minutes but was thwarted by Oxlade-Chamberlain - after Ramsey needlessly conceded a corner.
Villa's threat had waned though and Arsenal were in cruise control as they eased to victory.