SUCCESS is a hard thing to deal with. It is hard enough to deal with your own, but the success of a partner or best friend is ten times harder. Take Joe Orton. He was the one success happened to; his boyfriend was the one it passed by. So he hacked Orton to death with an axe.

So far this Wimbledon, there are no signs of Lleyton Hewitt taking an axe and giving his girlfriend 40 whacks. Kim Clijsters was positively blooming yesterday — in fact, the nearest thing we had to a sunny interval was the Clijsters smile. It came, as you might expect, in victory.

And there was Hewitt in the stands, watching her. Hewitt is the title-holder in the men’s event, the No 2 player in the world, a near certainty for a repeat victory in the eyes of sane and sober judges, and he was knocked out in the first round and looked like a guy going slowly nuts.

That same day, Clijsters won her opening match love and love. They are renting a house together for the duration of the championships and presumably Clijsters didn’t dance about the house singing: “It’s all gone quiet over there.”

And, touchingly, he is still there, cheering for Kim yesterday behind his wraparound shades and baseball cap. He is such a snarly, surly bugger on court that you would have thought the first thing he would do is storm off in a frenzy of hate. Instead he had stayed to play out a love game in SW19.

Clijsters is going through her draw like an accomplished flat-track bully. She dropped just seven games in her first three matches, as many as Hewitt lost in the second set of the only match he got to play. Yesterday, she came out of the trap like a greyhound, one that “pinged its lid”, in doggyspeak. After four minutes, she was three games up without conceding a point against Ai Sugiyama, of Japan.

Sugiyama collected herself after that. She is one of those players who, when in halfway decent form, insists that a player must hit at least three clear winners per rally if she is to win a point against her (Clijsters would have known this, of course, since the pair are doubles partners and later teamed up to win their third-round match in straight sets). Sugiyama made Clijsters work, but, with her big, swirly forehand and athletic movement, Clijsters won 6-3, 6-2.

So we can all start polishing up the Famous Belgian jokes. Examples: her Dad, Leo, was once Belgian footballer of the year and her mother, Els, is a former gymnast. That makes a change from Tintin and Plastic Bertrand, anyway.

Clijsters is playing like a winner. She has just turned 20 and, given that female players mature early, is in her prime. It’s time she won something big and she has the game to do it here. The question is whether she has the brain to take the next step — she was, after all, 5-1 up in the third set against Serena Williams in the final of the Australian Open earlier this year and then put together the best choke since Jana Novotna blubbed all over the Duchess of Kent.

But after a total of just three hours on court and four opponents trashed, she is full of bounce. Bounce is the quality at the heart of her game: she has an engaging, tigerish quality as she moves about the court. She is also regarded throughout the game as one of the Nice Ones. Admittedly, that’s not a hard accolade to earn in women’s tennis, but you fancy Clijsters could earn it in more exacting circles.

She plays with enjoyment as well as with relish and is quite delighted to have Hewitt mooching around the place. She was asked who was supporting whom this week. “He’s definitely helping me,” she said, a smile leaping unbidden to her lips. “It’s always nice it doesn’t always happen you know to have him in there in the box it’s always special to have him there yeah.” She speaks her English fast, fluent and unpunctuated, a bit like Inspector Clouseau reading the Molly Bloom soliloquy.

The trouble people have with a partner’s success is not simple envy. There is also a terrible insecurity. You might genuinely rejoice at a partner’s success but fear the effect it will have on the relationship. Success, unevenly distributed, puts all kinds of stresses on things. A relationship that prospered in poverty can fall apart when success comes to one and not the other.

It’s not bitterness. It is more that the dynamic of the relationship has changed. The year of struggle can be fun; it is in comfort that the tensions become clear. But there was Hewitt, a man at war with the world, wholeheartedly backing his girl and there was Clijsters blasting another opponent out of the way and beaming up at her box in her moment of triumph. A nice moment on a day short of beams.

Oh well, I suppose it’s time for a famous Belgian. How about Siger of Brabant? Not a household name, I admit, but Siger was a 13th-century philosopher and was mentioned, by implication favourably, by Dante. But he fell out with Aquinas and was condemned for heresy. He died in Orvieto, assassinated by his own secretary, who was perhaps unable to cope with Siger’s success.