BECAUSE it’s South Africa, people ask me about Jannes Labuschagne: 11 months ago, the game at Twickenham, that tackle.

This is how I remember it. It was early in the game, the ball had come back to me and I kicked it away. I don’t recall Labuschagne’s hit being particularly late but it did feel different. Maybe I wasn’t expecting it, maybe my body wasn’t quite ready to take it. I was in mid-air when he hit me and I’m thinking “it’s a big hit, right, the floor’s coming soon, I’ve got to try to land without hurting myself”. I fell and immediately felt the hit through my neck. I stayed down. You don’t mess around with necks, so I waited for the doctor.

And that was it. The doctor gave the all-clear and I didn’t have a moment to think about it — you’ve got to concentrate on the game. But it doesn’t stand out as the biggest or worst hit I’ve taken, neither does it haunt me and I’ll not take a single thought of it into today’s game. It’s hard enough to do all your preparation without thinking what if this happens, what if that happens.

Labuschagne was shown a red card but I honestly don’t think we’ll get that sort of stuff from South Africa today. We’ve been shown some tape of their recent rugby and it is really remarkable. It proves for good that the autumn series is a long time gone. What struck me is that they play true to the hallmark of their game: the physicality and aggression that is often talked about sit perfectly with them.

The aggression and physicality in defence, the organisation and the reading of the game, switched-on minds but fired-up attitudes — it’s a balance they have perfected. Their defence is hard but not reckless, the tackling is aggressive and pacy but not risky or illegal. That is what has stayed with me, that they are able to put in that physicality without having to sacrifice anything else. So we have to front up to that challenge.

If you are reading this on the morning of the match, you will find me in a hugely nervous state, a feeling where I can’t keep still, a hanging-around feeling, constantly on edge. It’s uncomfortable and I’ll be stuck with it. Most of the time, I’ll be in my room, my mind might relax for a bit and then it will suddenly click back into thinking about the game. If I think I’m becoming too obsessed by it, I’ll try to kick out of it. I might watch TV or read a book to take my mind off it but then, suddenly, it will wander back.

I’ve spoken a bit since I’ve been here about this anxiety and it’s been interpreted by some of the local press as a weakness. I hear that Rudolf Straeuli, the Springboks coach, said that I was putting too much pressure on myself. But they’re getting me wrong. It’s not because it’s South Africa or the World Cup game. It’s just the way I am, I can’t get away from it. I’m being honest about my personality and it’s something I’m happy to be honest about.

The pressure I’m under is put on by me. It’s always been that way. From when I played as a four-year-old, the morning before a game has always been the same. I got hugely nervous playing under-12 rugby and I get hugely nervous playing in these games, regardless of who it’s against. The pressure is about meeting expectation, pulling my weight, not letting people down. It means so much because I know how terrible I feel when I don’t.

At least I can sleep now. The night before a game used to be a real barrier. I’d wake in the night thinking about it and then the closer the morning got, the greater the struggle to get back to sleep. I’d just be lying there thinking about the game.

I’m better at that now. My preparation allows my mind to rest a bit more peacefully. But on waking, the anxiety will have kicked in and it will only increase the closer the game gets. Only when I get on to the pitch is there finally some release.

Jonny Wilkinson is writing exclusively for The Times during the World Cup. His next column appears on Tuesday