London: There’s a curious pain in watching an unforced error from Roger Federer.

There’s a tendency to wince, to close your eyes for a moment as if to shut out the reality. It offends our sense of what is fitting.

And there were a good few mis-hits and misjudgments on Monday. There was that elaborate rolled backhand with the flourished follow-through: but the ball goes up and stays up. The forehand that comes sailing out of the racket at the wrong point of the swing to fly grotesquely long. The shot off the frame of the racket.

All players make errors but with Federer — and only with Federer — it feels that the fault lies not in the player but in reality. And on Monday quite a lot of it was rather humdrum and some of it was what with another player I would feel comfortable in describing as poor.

Never mind. We still had a bit of Proper Rodge: the second set was straight from the High Fed period and the closing four games were filled with that serene certainty that Federer always did best. He beat Xavier Malisse 7-6, 6-1, 4-6, 6-3, but not without a fair bit of drama.

What a day. Coldest winter I spent was a summer in San Francisco, said Mark Twain, who never visited Wimbledon. There were gusts swirling round and round Centre Court, conditions ideal for the wind-assisted 400 metres. There was a just-perceptible drizzle throughout: if only they'd build a roof over this place.

Hang on, they’ve got one, haven't they? I distinctly remember it being closed all one day last week when it was bright sunshine, so keeping it open in the rain was only being consistent. And Federer wasn't happy out there at all. His back went in the first set and - most uncharacteristically - he had a medical time-out. It was, he said later, the after-effects of his five-setter last Friday combined with the vicious chill.

Mind you, whatever the doctor gave him, I’ll have a large one. He came back to play a near-perfect tie-break and took that second set in the grand manner.

Then he lost a really rather ugly third set — Federer losing concentration? Federer getting sloppy? - and then lost the first two games of the fourth as Malisse took every encouragement from this dip in form.

For a while, Federer looked human out there. Well, of course he bloody did. I have breaking news for you on this subject: Federer is human. That's the marvellous thing about him: he can do all these wonderful things and yet - and I am certain I have the truth here - Federer is every bit as human as I am; as you are.

He’s not a god. He’s not a magician. He's not one of the immortals. He’s a bloke, and that’s the marvel of it. In Othello, Iago sneers lubriciously of Desdemona: “The wine she drinks is made of grapes.” She’s not a reincarnation of the Virgin Mary: she’s as human as you are.

Federer also drinks wine that’s made of grapes. He sleeps in the night and is awake in the day. He gets up and has breakfast and his body does all those things human bodies do. He has arms with hands at the end of them and legs to run and eyes to see with and a brain to think with, but most of us have most of them.

But he has used them to come up with the impossibly brilliant tennis that took him to 16 grand-slam titles. He is capable of error, he is capable of self-doubt, he is capable of fear, because these things are the birthright of all humans.

But he produced (and intermittently still produces) greatness, and I think it is more helpful to think of greatness as something human rather than superhuman. The errors committed by the Federer of these later years reinforces this extraordinary truth. That’s why it’s good to see those errors: not because they reduce him to the level of the rest of us, because they don’t. Rather, they emphasise the greatness of what he has done. That's the nature of his greatness: something to do with humanity.