There is a period that comes after a viral illness when you assume that life will always be like this, that it’s perfectly natural to feel shagged out half the time, that it’s inevitable you are always a fraction below your best, that life is naturally harder work than it used to be and much, much less fun. You look at life through grey-tinted spectacles and think that’s the colour that the world exists in.

And then you wake up one morning and it’s as if a 50lb rucksack has been removed from your back. You find yourself making jokes. You find yourself laughing at them. You feel as if you could run for ever and leap tall buildings. I wonder if that’s how Roger Federer feels after a few months post-glandular fever, a time during which the whole world had been bathed in the perfume known as Essence de Crap.

There is a period that comes after you have been travelling in a series of difficult and hostile environments. You come to a place you know and love and, suddenly, all life’s hassles are doable and all those things that got you down seem of no importance; when all that was hard becomes easy and all that was beyond you seems suddenly within your grasp. I wonder if that’s how Federer feels after a return to Centre Court. “Every time you walk out, it’s beautiful,” he said. “The grass is perfect. You feel like nobody has walked on it. It felt very special again.”

Federer is back in SW19 again and, suddenly, I want to change sides. Suddenly, I want to play Angel’s Advocate. Suddenly, it really matters to me that Federer wins his sixth successive Wimbledon title. Suddenly, I’m a believer again, although, admittedly, it helps that Rafael Nadal doesn’t play until today.

But, hell, Federer beat Dominik “Getta Vowel” Hrbaty 6-3, 6-2, 6-2 yesterday and if it was patchy in places, the bits that were good were so good that it seems that beating him would be an act of violence against nature. His first round is done and the only really nerve-racking matches are the first and the final, Federer said. “The rest is OK.”

But, look, we are nearly halfway through this piece and we haven’t discussed the cardy yet. Apologies for this appalling journalistic oversight; and to think I was always taught on the Surrey Mirror to get the most important stuff in the first paragraph.

But, yes, Federer did indeed step out in a cardigan yesterday and even though the day was — remarkably, perhaps uniquely for a first day of Wimbledon — coming up to the boil, he kept it on for at least half the warm-up. Is that cool, or not?

It looked a very nice cardy, if you happen to be a cardy sort of man, a cardy you could easily stroll to the fridge in, relax in front of the television in; even, God help you, play a round of golf in. Federer pushed the sleeves back to the elbows for the dashing, “just about to do the washing-up” look.

And now for the amazing bit. He took it off without undoing the buttons. Imagine that. He pulled it over his head as if it were a pullover. Dreadful thought — perhaps the buttons don’t undo. Perhaps his sponsors have cut a few corners.

“It’s a little bit more easy to wear than the jacket,” Federer said when this most important topic was ventilated. Certainly, this will be an important chapter in the doctoral-length thesis on Great Woollies of Wimbledon, but I can think of two better. The first is the sleeveless jumper worn by Jeremy Bates in 1992, when he reached the fourth round, punching well above his weight, while wearing a woolly to protect a poorly shoulder. But, alas, he took it off in the fourth round and so, inevitably, he lost to Guy Forget.

The Wimbledon woolly of all time, though, is the pink cardy worn by Virginia Wade when she won the women’s singles here in 1977 — surely the woolly of all woollies. Federer’s cardy has some way to go if it is to match the little pink job.

But as cardies go, it started out the right way. Federer reeled off the first 11 points, prompting speculation that he would be the first man to win Wimbledon without losing a point. Back on Centre Court, he looked as if he had turned back into Rodge again. The man hagridden by worries, and by his self-imposed duty of pretending that he had no worries, seemed to have vanished.

This was not an exhibition of perfect tennis, but there were passages of play in which perfection was pretty close. The dangerous, rolled, top-spin backhand was finding its range again, the fiendish, top-spin forehand was doing its usual frightening thing of going out and then changing its mind at the last minute and insolently clipping a line. I don’t know if he can win, but I can tell you one thing for sure: the person who beats him will have to be seriously bloody good.

For this was something of a reaffirmation of all the things Rodge, a timely reminder that Federer in decline is better than practically anyone else who has picked up a racket.

And Federer’s message yesterday afternoon can be summed up simply enough: what decline? Damned if I could see one.