Ozil stuck on periphery as Bendtner cameo exposes Gunners' depth
No team who wins at Borussia Dortmund and leads the Premier League by two points at the end of Remembrance Sunday can be placed in a coconut shy for losing to a majestic Robin van Persie header at Old Trafford.
To dismiss the Arsenal revival after such an explainable setback would be intellectual vandalism.
The Gunners, though, are up against a peculiar form of fatalism. Sweepstakes are being held on when the revival will end. Rarely has an upswing been accompanied by so much scepticism about its ability to last.
Some of England's best football minds have declared with unusual force that Arsenal will not win the Premier League title after eight years (or nine, by next May) without a trophy.
Why the doubt? Well, the psychological damage from all those years of selling the club's best players was never likely to be repaired by one good start to a campaign; nor by an expensive lunge into the transfer market to sign Mesut Ozil.
Travelling north on trains, Arsenal's fans were more buoyant than in recent trips to United's lair. For the first time in recent memory they could claim to be supporting the superior side.
The 8-2 defeat here of 27 months ago had been laid to rest. In successive games, Arsenal had beaten Liverpool and Dortmund.
They were leading the dance in the most unpredictable Premier League title jig for years. There was no solid reason to expect an implosion in the current campaign. The days of rancour and regression were receding with each encouraging result.
An optimist might argue that Arsenal lost here partly because the effort of beating Liverpool and last season's Champions League runners-up drained them.
Per Mertesacker, the German centre-back who might have challenged Van Persie from Wayne Rooney's corner (which produced the only goal of the game), was unable through illness to take part.
Less charitably, it should be pointed out that in the second half Arsenal were able to deploy almost their full array of creative talent but were still unable to break through the red block of United shirts.
The stock of Arsene Wenger's men has risen so fast that the sight of Ozil, Aaron Ramsey, Santi Cazorla and Jack Wilshere (from 60 minutes) all probing for a goal produces an immediate expectation of bulges in opposition nets. Not this time. First Arsenal were reminded yet again of the cost of losing world-class players, then their rhythm section displayed worrying fallibility.
Wenger may still call Van Persie an "Arsenal man", but he is so long gone that he now celebrates goals against his old club with unreserved pleasure.
The opponent he beat for the header, Olivier Giroud, has improved considerably in the last six months. But he is not in Van Persie's class. Nor should he have been the defender engaging United's best player when Rooney's cross arrived.
Unusually for a Wenger team, Giroud is developing some of the roughhouse qualities of the George Graham era. His early stamp on the foot of Jonny Evans offered a sign that Giroud would not be shying away from combat with United's two centre-backs.
In a goalless performance, Giroud was bound to look a notch or two below Van Persie and Rooney.
Applaud him, however, for applying himself more vigorously than Ozil, Cazorla or Ramsey, whose decorative play lacked the hard edge necessary to keep Arsenal's winning run going.
Ozil, remember, was available to United at least twice. Once in the summer of 2010 and again in the last transfer window.
Neither time did Alex Ferguson or David Moyes show much interest. Instead he arrived at Arsenal as a record signing and talismanic figure. If the only audible doubt about him is that he sometimes drifts out of the action then this was a day for believing such gossip.
The greatest No 10s demand the ball incessantly. They go looking for the heart of the game and try to shape it in their image. Ozil does this often, but not always. On his off days he can seem peripheral and cut-off.
He shouldn't carry the can alone. The threat Ramsey has carried into games this season deserted him and Cazorla was also innocuous. Matthieu Flamini, the guard dog, gave way to Wilshere after an hour as Arsenal chased parity.
No sight undermines belief in Arsenal's title-winning credentials quite like Nicklas Bendtner bounding on with his samurai haircut.
Many of us assumed we had seen the last of Bendtner in an Arsenal shirt after his disastrous League Cup performance against Chelsea.
In his current state he seems to go up and down on the spot. The mechanics of football at this level appear beyond him. (© Daily Telegraph, London)