Sir Alex Ferguson's side dominated at the Theatre of Dreams to make it three wins in three so far this season for the hosts and add further woe to the hapless Gunners
A Wayne Rooney hat-trick and a brace for Ashley Young, as well as strikes for Danny Welbeck, Nani and Park Ji-Sung exemplified the gulf in class between the two sides, as Theo Walcott and Robin van Persie replied with strikes worthy of mere consolation.
Sir Alex Ferguson insisted that Manchester City’s 5-1 win away to Tottenham earlier on Sunday would have no affect on his team prior to kick-off but with their noisy neighbours raucous in the capital, there can be little doubt that the Scot will have expected a statement of equal intent from his charges against the league’s other north London side.
He named an unchanged side for the clash, with both Welbeck and Tom Cleverley rewarded for their fine recent performances with starting berths.
The youthful make up of the hosts was somewhat mirrored by their opponents, with Arsene Wenger giving 20-year-old Francis Coquelin his league debut, though it appeared a decision borne out of necessity, with the visitors’ squad left threadbare due to a number of recent injuries, as well as the departures of Samir Nasri and Cesc Fabregas.
Arsenal were offering promise going forward but the air of inevitability surrounding an opener for the home side was soon justified in painful fashion for Wenger, as Anderson's fine lofted ball was allowed to bounce in the box by the Gunners' inexperienced defence, allowing Welbeck to nod home with ease on the 22nd minute.
As the French boss watched on like a man down on his luck, his side were offered a somewhat fortuitous opportunity of getting back into the game, as Theo Walcott fell in the box under pressure from Jonny Evans. The assistant referee deemed it worthy of a penalty to the disbelief of the Northern Irishman but as Robin Van Persie saw his weak effort from the spot saved by the under-fire David De Gea, you couldn't help but feel that the perennial nature of Arsenal's decline was being played out with almost satirical predictability.
Champions flying | Ashley Young celebrates after doubling United's lead
It was a case of it never raining but pouring for the Emirates outfit as only a minute later Young doubled the hosts' advantage. After seizing on a poor clearance from Armand Traore, the former Aston Villa man bent a simply beautiful effort past the stretching 6ft 4in frame of Wojciech Szczesny to further exemplify his seamless transition into his new side.
Andrey Arshavin was fortunate to escape a red card following a foul worthy of a second bookable offence on Young and the impressive Welbeck was cruelly forced off with a suspected hamstring pull but any suggestion that the tables were turning back in the favour of the visitors was quashed with the Red Devils' third as Rooney converted a sublime free-kick following Jenkinson's foul on Young on the edge of the area to pick up his 150th United goal.
If any Arsenal performer deserved a reprieve it was the lively Walcott and his early endeavour was rewarded on the stroke of half-time as he pulled a goal back for the visitors after latching onto Rosicky's through ball to offer a semblance of respect to the scoreline.
The poor defensive habits of Arsenal were proving to die hard however, and Tom Cleverley was allowed to run freely into the area to all but wrap up the game just wasted an easy chance into the arms of the grateful Szczesny.
The youngster's sin was atoned for soon after as Rooney bent another free-kick past the helpless Pole into the opposite corner of the net from his earlier strike. The game, with over 20 minutes remaining, was up.
However, the relentless attitude of the home side was not and they made it five soon after as Nani found space in the area following a simple pass from Rooney split open the Gunners' back line and chipped a lovely effort home.
The Red Devils then turned the knife further, as Arsenal's chief-tormentor in recent years, Park made it six. Van Persie grabbed a consolation soon after before Jenkinson was sent off to sum up an utterly humiliating day for Wenger and his side.
The perfect day for the Old Trafford faithful looked to have been neatly completed from the penalty spot as Rooney picked up his sixth United hat-trick following Walcott's push on Patrice Evra.
Yet the agony for the north London side was finally confirmed in quite fantastic fashion as Young got his second his another curling wonder-strike.
The home side's starting XI may have been younger than Arsenal's but following a ruthless performance of such quality at Old Trafford, Ferguson's sparkling kids proved once again that they are more than alright. Their opponents, it would seem, are anything but.