Sport's extraordinary power will help heal the wounds of Paris, just as it did in New York

We like sport. We love sport. But at times like this sport seems utterly, almost painfully irrelevant.

The horrific events in Paris on Friday that left 129 people dead have left a cloud over the world, with everyday life seeming meaningless and mundane in the face of such sickening atrocities perpetrated on the innocent.

In a world where such things can happen, where even in one of the world's great cities a normal Friday night's entertainment can turn into a massacre, how can we carry on as normal?

Yet we can. We must. And nothing is more important to carrying on as normal than sport. I know this because I've seen it in action before.

Back in 2001, I lived and worked in New York; on the night of September 10th, I flew from the Big Apple out to a conference in San Francisco.

The next morning - September 11, 2001 - I woke up at 6am to a string of confusing, almost baffling messages that made no sense until I turned on the TV and saw the live coverage of what was happening back in New York that morning at the World Trade Center.

It took six days before I was able to get back home, to a city still shell-shocked by the carnage that had unfolded when terrorists had crashed two passenger planes into the Twin Towers, leaving almost 3,000 people dead. An eerie quiet hung over the city, the dust and debris from the explosions still in the air. Nobody did anything. Nobody went anywhere. All conversations were held in hushed tones. The streets remained almost empty. The devastation was total, the world on hold.

A few days later, the New York Mets baseball game against their arch-rivals, the Atlanta Braves, went ahead at Shea Stadium. It was the first big sporting event to take place in the city after the attacks; indeed, the first major gathering of any kind, sporting or otherwise.

A Friday night baseball game at the Mets' cavernous ground might normally have been half-full, perhaps even less. That night in Queen's it was packed to the rafters - and the atmosphere was electric. Representatives of all the emergency services threw out the first pitch; the national anthem had tears streaming down every face; Diana Ross singing "God Bless America" had the same effect; and Liza Minelli singing "New York, New York" in the "seventh inning stretch" (a sort of late-game intermission in baseball) had the crowd on their feet in solidarity, sympathy and - yes - defiance.

Minutes later, the Mets' star player Mike Piazza hit a home run that gave the home side a narrow victory against the Braves. The crowd were on their feet again, roaring approval - and chants of "USA, USA" rang loud. It felt like a spark coming to life in a fire that you thought had gone out, a chink of light appearing on a night that seemed it would last forever. New York wasn't back, but that night at Shea Stadium it felt like the first step had been taken in a healing process.

What is it about sport that gives it such power? Many of us spend our lives in huge cities of millions of people, but are often isolated. Our social communities are often very small on a day to day basis, our lives predictable and controlled. Many spend years living in flats barely knowing the people who live a few yards away next door; travelling on trains and buses where our fellow commuters do everything they can to avoid talking to each other; or working alongside colleagues whose lives we know little about.

In sport, however, all that changes. The surge of raw emotion that comes with watching sport brings down barriers and creates connections; we cheer and roar and even hug total strangers, whether in joy or commiseration. We open ourselves up to each other in a way that is increasingly rare in the modern world, revealing ourselves and joyously sharing the emotional outpouring of others who share our passion. And in lives where our shared experiences rarely involve even a dozen people at once, we stand beside tens of thousands of like-minded people, drawn together by a shared experience.

I was there that day at Shea Stadium with a friend - both of us English, both of us swept up unashamedly by the mood, weeping and consoling with the native New Yorkers. That friend had been on the ground floor of the World Trade Center when the first plane struck, but he got away safely. Not everyone I knew was that lucky.

At Wembley on Tuesday night there will be people in the crowd who have felt the shock of what happened on a very personal level, who will have suffered bereavements among their nearest and dearest. But when 90,000 voices come together to sing La Marseillaise, they will at least know that they are not alone. And they will also feel the truth that sport, seemingly so meaningless at times of tragedy, carries with it a real power: the power to bring people together, whether in the best of times or the worst of times.