Contrary to what JA sometimes thinks (he says, having seen her school exercise books this week) I am not obsessed by sport. I can happily watch almost nothing of the Premier League, for example.

But I do like watching the big events.

For me, that means the snooker world championships, FIFA World Cup plus the European Championships, the Olympics, the athletics world championships, the NFL post-season .. and the Tour de France.

Yesterday showed one reason why: at his best, Mark Cavendish is incredible. He can't climb mountains, so he'll never win overall, but given a bunch sprint on a stage, he's going to be in there. Last year, his tally of six stage wins – a British record – included the final stage ending in Paris.

When you watch that video, which starts from about 5km from the finish, note that sprints are often decided by centimetres. Yet in the final kilometre, everyone's going at well over 40mph but 'Cav' and his pacemaker make it look like the rest are standing still. I suspect the helicopter shots don't show just how far ahead he is to spare the rest's blushes. Ten lengths? When your pacemaker comes second, you know you've had a crushing victory.

But he's had problems this year. On Sunday's stage one, he had a minor crash on the last sharp bend. On Monday, someone broke away from the bunch which then proceeded to have a series of crashes in the slippy forest roads and there was a group decision that there wasn't going to be any sprinting. Tuesday saw the route take in bits of the Paris-Roubaix cobbles and the field spread out through bike breakdowns. Wednesday, he was 'jumped' by someone in the final few hundred meters, couldn't keep up and gave up – his loss resulted in more headlines in the French press than the winner got!

So yesterday's stage, which could have been his third win this year ended up, very emotionally, as his first. Fifth or sixth at 300 meters to go, he won it by a wheel. Awesome.