It was that smile that got to me. I was never comfortable with it, not even at the start when she came at us clad in the publicity of innocence. I don’t believe she was ever innocent in her life, certainly not as an athlete in a confrontation sport.

Martina Hingis used to smile all the time. People said it was because she played with youthful freedom, with girlish abandon. She had all the girlish abandon of a Centurion tank. The smile was pure armour-plate, more a rictus of concentration than a signal of inner delight.

Perhaps she did it to annoy her opponent. To be beaten by a 16-year-old is bad enough; to be beaten by a 16-year-old grinning all over her face is a great deal worse. And annoying people was her greatest sporting attribute, and for that reason she was an absolute delight to watch.

She was one of the cleverest athletes I have seen. She had a flair, amounting to genius, for understanding an opponent’s weakness and contriving the game to exploit it. As women’s tennis became increasingly a game of power, Hingis fought back with the power of the mind.

And always with that awful smile. There was something elsewhere about her, something not quite of this planet. At her best, she seemed to be toying with earthlings for some kind of rather depraved amusement. She moved beautifully, and with deft and merciless precision dismantled one opponent after another.

There was something additionally disturbing about her for a male spectator. You weren’t quite sure whether you were allowed to fancy her. In certain lights, even when very young, she had the expression of a knowing, challenging and fully awakened woman, but at other times, this precocious maturity fell away and she was little more than a child.

Being a child star has its problems. You have to grow up in public and the mistakes of slammed doors and sulky stamps can become global events. I remember the Wimbledon when she sacked her mother. She had just lost half the world’s sympathy in an appalling display of temperament in the final of the French Open and she arrived at Wimbledon with her mother spectacularly absent. The gloriously independent Hingis went out in the first round, a sad and pathetic teenager in need of a good hug and a sob, millions or no millions.

Hingis was always able to dismantle the power game of her rivals, but as the Williams sisters came into their full strength, she lost her confidence at dealing with them when they came at her gang-handed. She could take one, but then the other Williams would generally have her in the next round.

Thus her confidence eroded. She lost her authority, though she always loved being a star. The best Hingis story concerns an exhibition match with Anna Kournikova; Hingis was always confident enough to believe that she could outdo Kournikova (or anyone else) in any sphere of excellence whatsoever. The women fell out at this event and had a fight with flowers; vases, too, I have been told. “You think you’re the queen,” Hingis allegedly said, “But I’m the queen.” She was right, too.

I was sorry when she retired, because she added to the variety of tennis life, and variety is vital to the health of any sport. Acid-tongued and possessed of an insuperable self-regard, she was often good value in press conferences, once kindly explaining that Amélie Mauresmo was “half a man”.

She then unretired, as those who retire young often do. Without a tennis racket, she wasn’t much of a queen any more, but more importantly, I think, she remembered that she loved playing the game: hitting the ball and bending her opponents into pretzels.

It would have been nice if she could have won more than her 43 singles championships, but when you retire, the game moves on and you lose that habit of going into those places that cause pain. But it was always a pleasure to catch a Hingis match: to see that incomparable tennis mind operating in all its grace and ruthlessness. Shame about the drugs test result: nasty way to end it all. But as I say, she was never innocent.