The fan - Hunter Davies sings along to the Euro music

I can't make out the words of the Euro music except for "LASAGNE!"

I should have realised it was going to be an unusual game as soon as I arrived. "Can I look in your bag, sir," grunted a security woman. I have this little black rucksack, so small and bijou you can hardly see it, sort of plasticky, only £2 from a stall in Camden Town. I always carry the same essentials - flask of coffee, orange, chewing gum, petit umbrella. Not once in ten years, taking it to White Hart Lane, Highbury and Brunton Park, has anyone asked me to open it.

"What's going on," I said, half thinking it must be something to do with the game, quarter-final of the Champions League, yet drawn against Chelsea, another London club. Could be expecting crowd trouble.

"Iraq," she grunted. "Thatswotsgoingon."

I do love these European games. I am amused by the words "Uefa Champions League" in all the official literature, without no sign of no apostrophe. So bugger Lynne Truss.

I like the kids standing to attention before kick-off holding little corners of the vast circular football tablecloth, waiting for the secret sign to start shaking it at the billions watching round the globe. I keep waiting for some kid to drop it. I love the Euro music, and yet in all these years, as I sing along, I still don't know the words. All I can make out is "LASAGNE!" which I belt out, ever so lustily.

I want Arsenal to win because my Arsenal friends will be happy. But unlike them, I won't be emotionally distraught if they don't. I want them to carry the flag for English football, progress further, as it will mean I'll have an exciting semi-final to watch against Real Madrid. By good luck, my half of the season ticket I share has included all the top games.

It was true they'd had a nasty shock against Man United, knocked out in the FA Cup semi-final. That was a sickener. But in the Premier League they were still unbeaten. At the previous League game, the programme had included two large features on "the many records created throughout Arsenal's glorious history", which now included the longest unbeaten run in any one season. Boasters. At least Arsene Wenger has not tempted fate this year by predicting they might go a whole season unbeaten.

In the previous two months, I had detected slight signs of slackening. Against Charlton and Bolton, they'd won only 2-1 and in the second halves they were fortunate to hold on. At the time, I'd thought it was overconfidence. Thierry Henry can be too cool, deliberately low-key when he scores and quietly arrogant, which must infuriate the opposition. But after the Man United defeat, I had decided the answer was simpler - Arsenal were knackered.

It's not just fresh bodies you need at this stage, but fresh ideas. Claudio Ranieri, by tinkering all season with Chelsea's large squad, had fewer tired bodies and tired minds. I also wondered whether it was a devious plot by Roman Abramovich to indicate that Ranieri was for the chop in order to unite the team behind him.

When Wayne Bridge scored Chelsea's winning goal, three minutes from time, a remarkable thing happened. Around me, Arsenal fans left in their thousands. At Spurs, people pile out of the West Stand ten to 15 minutes before the end of every game, regardless of the score, effing and blinding. In 30 years of going to Arsenal, sitting in their West Stand, I have no memory of ever seeing so many leave so early.

It was eerie, at the final whistle, descending the concrete stairs. Total silence, as if they had come from a funeral, heads bowed, minds numb. Usually, people are shrieking and shouting at each other or into their mobiles. I imagined the phones vibrating in their owners' pockets but being ignored, the tragic event just witnessed having dumbed all senses.

What an unexpected result, and how strange the atmosphere, though nothing as weird, I assume, as at Real Madrid and AC Milan. The whole European hierarchy made a nonsense of in just two days. Not that it bothers me, being a football tart. Come on, you Blues . . .