English FA Premiership: Manchester City, as Kevin Keegan put it, performed a pre-match x-ray on Arsenal and found all the parts to be in magnificent working order. A 90-minute examination here revealed Arsenal as less than perfect, even if any weaknesses are psychological rather than physical.

Arsene Wenger was more concerned with the latter in his post-mortem and seemed puzzled by the results. "We dropped physically in the second half," he said. "We are a little less sharp than at the start of the season."

But is this tiredness in the head or in the body? Teams in Arsenal's grand position are readily accused of arrogance and self-admiration. Call it complacency or relaxation, but England's pre-eminent team allowed a committed Manchester City hope when there should have been none.

The outcome, nevertheless, was a now uncustomary 1-0 to the Arsenal, a refrain to which their fans returned in between the current favourite, "We are unbeatable". They have 47 reasons to chant it but it still sticks in the throat of opponents.

Manchester United, next hosts of the Arsenal Premiership roadshow, need no extra motivation, especially as the champions will probably arrive at Old Trafford aiming to make it 50 not out.

Keegan admired the innings so far. "We gave them a severe test and asked them, how good are you? The answer is very, very good. We've found a level we haven't found too often in the past and they still beat us. They've got quality through the side; we haven't got that."

Arsenal's quality will see them through against better teams than City but it will have to be applied more rigorously. Thierry Henry strolled, Dennis Bergkamp made minimal impact, leaving Ashley Cole to emerge as the most menacing attacker.

And, given Nicolas Anelka's sustained threat, it was just as well that Sol Campbell, and not Pascal Cygan, was buttressing the defence.

Wenger paid City due credit. "They played a Cup game, physically very good. And they showed a side I didn't know they had. They were tenacious defenders for the 90 minutes. They showed a caution and the game did not open up for us."

It should have done once Cole took his early goal. If it was slightly fortunate - the ball rolling straight to him from Richard Dunne's attempted challenge on Jose Antonio Reyes - the full-back's deft flick from the outside of his left boot deserved reward.

Cole's willingness to surge deep into enemy territory almost brought the killing goal Wenger sought. Midway through the second half his cross-cum-shot rebounded from David James's near post. But the contest should have been put to rest long before that moment.

Arsenal's football in the first half was a thing of beauty. Their almost contemptuous domination of possession was signalled in the opening seconds.

Fredrik Ljungberg almost scored from Bergkamp's pass without a City player touching the ball; Reyes spun past James only to be eventually blocked; Henry calibrated an angled shot past James but just wide and then saw a volley parried by the goalkeeper.

Wenger's team created space in the final third of the pitch and squeezed it at the back. City looked to Shaun Wright-Phillips's pace to part this screen but, after crossing early on for Jon Macken to force a sprawling save from Jens Lehmann, the winger settled back into an increasingly withdrawn position in a bid to stifle the runs of the marauding Reyes and Cole.

Wright-Phillips's resurgence as an attacker prompted City's best periods, early and late in the second half. One beautifully measured cross was mis-kicked by Anelka, who also forced Lehmann into a scrambling save from Macken's pass.

Anelka was nothing if not persevering against his old club. Late on, his thunderous free-kick flashed inches wide and by this time Wenger had made more than one stone-faced appearance by the touchline.

The bare result does Keegan no favours but a straight-from-the-heart performance surely will. As he put it: "If there's such a thing as a good defeat, that's it, against a great side."