After failing to win in their first two Premier League fixtures of the 2011-12 campaign, Arsenal were under pressure to make an impression when they travelled to the North-West to face Manchester United at Old Trafford.
However, Arsene Wenger suffered a double blow in the build-up to the game as defensive duo Thomas Vermaelen and Bacary Sagna were ruled out through injury, leaving the Gunners with a relatively inexperienced back four which included new signing Laurent Koscielny.
As for United, they had started the season in style, and boss Sir Alex Ferguson had the confidence to name youngsters Phil Jones and Tom Cleverley in his starting lineup ahead of Rio Ferdinand and Park Ji-Sung.
The start of the game was dominated by United, with Danny Welbeck constantly getting the upper hand over Koscielny, but the English forward was unable to hit the target after breaking away from the defender in the final third.
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As the first half reached the midway point, Arsenal began to have a bit more success, with Theo Walcott seemingly having the pace to beat the United defence, but on 22 minutes, United opened the scoring through Welbeck, who flicked a header past Wojciech Szczesny after he had been found by Anderson.
However, Arsenal earned an immediate chance to equalise when Jonny Evans hauled down Walcott, but David de Gea made himself an instant hero at Old Trafford by saving Robin van Persie's weak spot kick.
It was a rare opening for the North London side, and they were made to pay two minutes later when United doubled their advantage. After receiving the ball on the edge of the penalty area, Ashley Young bided his time before curling a delightful effort into the top corner from 20 yards.
Arsenal were struggling to cope with the fluency of United's attacks and shortly before the break, the match was almost ended as a contest when Rooney made it three. The striker combined with Young before firing the ball past a helpless Szczesny.
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However, seconds before the half-time whistle, Arsenal gave themselves a lifeline when Walcott latched on to a Tomas Rosicky pass to force the ball past De Gea, who should have perhaps made a better attempt at keeping it out.
Despite having something to build on at the break, Arsenal were soon forced onto the back foot by their hosts, with Young looking every penny of the eight-figure fee that had been spent on signing him from Aston Villa, and he had a pivotal part to play in his team's fourth goal of the afternoon.
After a free kick was won on the edge of the penalty area, Young teed up Rooney to wrong-foot Szczesny and curl the ball just underneath the crossbar to put the result of the match beyond doubt.
It was a case of damage limitation for Arsenal, but in the space of nine minutes, they conceded two more goals as United began to run riot and send a message to their league rivals.
After being found by Rooney, Nani nonchalantly chipped the ball over Szczesny for the fifth before the sixth was scored by Park, who ghosted into the penalty area before rolling the ball past the goalkeeper.
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Van Persie reduced the deficit when he volleyed home from close range to make it 6-2, but things went from bad to worse for Arsenal with 13 minutes remaining when Carl Jenkinson was dismissed for a professional foul on Javier Hernandez.
Arsenal needed to hear the full-time whistle but United scored their seventh of a remarkable encounter when Rooney completed his hat-trick from the penalty spot after Patrice Evra had been brought down.
Young capped a fine individual display with another long-range strike in the final minute before Wenger's misery was compounded when he was sent to the stands as his frustration boiled over on an embarrassing afternoon for his side at the Theatre of Dreams.
