The idea of more than a year going by without either of the Williams sisters winning a Slam would have been inconceivable a couple of years ago. It is indicative of how much they have fallen — or how much others have caught up — that even with them now both back from injury this US Open still looks wide open and we haven’t been able to say that in a long while. It’s not easy to stay ahead of the game. I’m not suggesting what happened to me is what has happened to them but the scenario looks familiar.

It’s only natural that they will have wanted to enjoy the fruits of their labours, but in this game you have to work harder just to stand still. I remember I made the mistake of thinking I was a cut above the other players and instead of continuing to work at my game I sort of said, “Well, let’s wait and see what the others do”.

Like the Williamses, I had six months off from tennis, in my case in order to spend more time with my first-born son. But when I came back — and after all six months isn’t that long — things had changed. Maybe I inspired them to work harder, guys like Ivan Lendl.

All of a sudden they won a couple of big matches and the aura which I thought I had started to fade and with it my confidence. The way in which young Maria Sharapova attacked Serena Williams in the Wimbledon final this summer was a classic example of that.

No doubt the Williamses will point at injuries as the reason for their temporary decline and maybe they’re right. Maybe, too, they’ve been distracted and the reason for the injuries is that they haven’t worked quite as hard as they used to. Who knows.

Unlike Serena, Venus doesn’t look quite as physically imposing as she used to. It’s difficult to put your finger on what has been wrong with her game. Maybe they were both over-tennised. One thing is certain: they are great for the game, Serena in particular with all her outfits.

The latest one, with the knee-length boots, takes me back to the time of my old friend Vitas Gerulitis and Studio 54, which was the night-club of the time. I would go there occasionally with Vitas and they would roll out the red carpet for him, but I could never seem to get in without him, despite my protestations that I was No. 5 in the world.

It was like “Get out of here”. I thought, “God, this is an incentive to get better, five in the world isn’t good enough, I need to be one or two”. I’m sure Serena doesn’t have those kind of problems, but people will look to knock her down if she doesn’t back up the fashion and the photo-shoots with her tennis. It’s an unforgiving, sometimes brutal, sport as I was reminded for the umpteenth time watching a tearful Daniela Hantuchova lose to Patty Schnyder on Friday. It is like being undressed in public and is about as lonely as a boxing match.

At least in boxing if you freeze some guy will, more than likely, pop you and put you out of your misery, but in tennis there is no escape. But to get back to work ethics.

That’s why I give credit to Tim Henman and my birthday wishes, too; he’s 30 tomorrow. He continues to work hard at his game. For example his forehand is a much better shot these days than it ever used to be.

But sometimes even working hard at your game and improving isn’t enough. Lleyton Hewitt is a highly dedicated player, who looks certain to make the semi-finals after the defeat on Friday of both David Nalbandian and Sebastien Grosjean who were in his quarter. I’m sure the Australian thinks he’s a more rounded tennis player than he used to be and maybe he is, but he still isn’t playing with the same confidence as he was when he was winning Wimbledon and the Open a few years ago.

Someone who clearly is, is his prospective semi-final opponent Andy Roddick, who blasted the excellent young Spaniard Rafael Nadal out of his path in straight sets late on Friday.

It was even too much for last year’s finalist Juan Carlos Ferrero on Friday — I’ve never seen him get so mad — but Roddick, the reigning champion, is positively energised by it. I’ve seen nothing so far to dissuade me from the view that he will win it again this year.

If only all the Americans could thrive on it in similar fashion. After hitting a new low at the French Open, when no American man advanced to the third round, US men’s tennis took another definite turn for the worse with just two survivors — Roddick and Andre Agassi.

This is the worst showing by the host nation in Open history. I had hoped after his Olympic exploits that at least Mardy Fish would make a decent fist of it here but even with the enticement of an intriguing third-round match with Henman, the fifth set of his match against Michal Tabara, of the Czech Republic, was disappointing.

Perhaps it’s all come too easily for Fish. Taylor Dent’s lack of progress has been more difficult to fathom. He just doesn’t seem to pick up on what he needs to do at the crucial time. It looks like my brother Patrick, who is US Davis Cup captain, will have to rely on Vincent Spadea for their forthcoming tie.

He’s a trier but even that wasn’t enough against Austria’s Jurgen Melzer. The worst of it is when you see a great talent like Marat Safin going to waste early in a Slam. The sport needs players like him because he is a genuine Slam contender.

Another is the Australian Mark Philippoussis, whose father rang me last week to ask if there was anything I could do to help his son raise his game. Like Safin, for whatever reason, the big fellah just hasn’t been able to carry on his success of last summer at Wimbledon. Sometimes, though, you find yourself in awe of the modern-day tennis player, particularly his power.

Watching the young Swede Joachim Johansson hitting 139mph serves out wide on Friday against another big hitter, the young American Jan-Michael Gambill, made me grateful that I play on the seniors’ tour these days. It also made me want to go out and hit a few balls myself, see if I still had a 110 in me. With the wind behind me.

The Sunday Telegraph