The picture had been chosen for its utterly gratuitous depiction of female beauty. It showed Justine Henin, the Belgian tennis player who won seven grand-slam singles titles between 2003 and 2007. She was fully dressed for tennis. The gratuitous beauty came from the shot she was playing. It was a single-handed backhand.

Henin was five foot six and so slim she had to run round and round in the shower to get wet. She didn’t look capable of hitting the top off a dandelion. But that backhand regularly devastated opponents, fizzing down the line with astonishing power — where did that come from? — or howling across court at a quite preposterous angle.

But now, as we enter the Australian Open, the first grand-slam tournament of the year, it’s clear that the single-handed backhand is becoming extinct. Practically all the women and a clear majority of the men prefer to put both hands on their rackets and take a great meaty axe-murderer swipe at the ball.

Roger Federer still plays the single--fister, and does so as beautifully as he plays every other shot, including patting the ball back to the ballboy. But Federer is 33 and in decline, and the shot is declining with him.

Stan Wawrinka, another Swiss player, also plays the one-hander and it has taken him to the highest levels of the sport. But he has few imitators. The New York Times worked out that there are only three women in the top 100 with a single-handed backhand, and 24 in the men’s — most at the wrong end of a career.

This is a sad thing because it’s a lovely shot to watch. There is an aesthetic pleasure in watching all sports — why else do we have goal-of-the-month competitions? People purr about Moeen Ali’s cover drive (when it works) and David Gower is still celebrated for the loveliness of his batting style.

Federer at his peak was loved for the way he seemed to transform sport into art. His sweet backhand was a vital part of this beauty, this love. There always seems to be an element of magic involved. It doesn’t look physically possible to hit the ball hard with the racket on the wrong side of our body. You’d imagine that the best you could hope for is to block the ball back in court and hope the next shot arrives on your natural ball-whacking side — which is precisely how the game is played at the duffers’ level.

But Federer and Henin and the other great single-fisters play the shot with speed and power and spin and accuracy. It’s not about muscularity, as Henin’s physique makes clear: instead it’s all in the mysteries of timing. Remember John McEnroe? He was no Mr Universe, but his backhand went like hell — and right there you find the aesthetic appeal of the shot.

It looks like something for nothing: as if gravity and the laws of physics have been suspended for the specific benefit of the ball-striker: in the manner of a Lionel Messi dribble, a Jonny Wilkinson drop goal or the Gower flick-pull.

The one-handed backhand has some serious advantages to the user. You can reach further, so it’s a great help in what tennis players call a ‘get’. You can generate great slice, or underspin. And best of all, you can find some devastating angles.

The greatest volleyer of them all, Pete Sampras, converted from a double to a single-fisted backhand. The backhand volley when he came in behind his monster serve was a form of assassination: first the bludgeon, then the rapier.

But modern players prefer the double-fister. It’s easier, and it has great power. These are days of powerful, muscular players with lightweight hi-tech rackets. A single-handed backhand, it’s believed, can be overwhelmed, for attacking the backhand is the most elementary tactic in the game.

The double-fister is also easier to coach. It brings a player gratification a lot quicker. It can take years to get a single-fister working reliably; much easier to coach the double. Most players will never even consider the advantages that a gorgeous and well-crafted single-handed backhand can supply.

Players are faster and stronger in all sports. These days every single part of life is an aspect of training and preparation. Equipment changes. The great champions of the very recent past would have had no chance against the players of today.

And sport is all about seeking and holding an advantage. If you play better than your opponent, you win and you’re happy. If you don’t, you lose and you’re miserable. It follows, then, that no tennis player in the world is going to work on a shot because you happen to find it pretty.

Sport is often pretty — often enough sublimely beautiful — but never, ever on purpose. Sport can only be incidentally beautiful. Dancing Brave may have been the loveliest horse that ever printed his proud hooves in the receiving earth, but he was bred for speed, not beauty. There were no marks on offer for artistic impression when he won the Prix de l’Arc de Triomphe in 1986.

Gower didn’t play those beautiful shots to please the eyes of those watching. He once showed me — we were doing a gig for the excellent charity the World Land Trust — the flick-pull in slow motion and it looked even less possible than it did at full speed. ‘You just feel the ball on the bat…’ and it was beautiful all right. But he played it because it was the best way he knew to score runs for his team — a comparatively sordid notion, but central to the sporting life.

Sport follows the brutal logic of natural selection. If something works, it proliferates, while old-schoolers can only make futile complaints. Ski-jumping purists hated the ‘flying V’ technique — but it gets you further down the hill and it’s now ubiquitous. The reverse sweep in cricket was deplored as an affectation, but it’s now standard. People said that the shorter forms of the game would kill the loveliness of spin bowling, but here the reverse has happened. That’s because spin bowling works in the modern context.

When Dick Fosbury went over the high-jump backwards, people thought he was a nutcase. As his technique, the Fosbury flop, gained acceptance, people mourned the passing of the straddle and the western roll. Andy Murray will be out at the Aussie Open playing his double-fister with all the power and control that took him to the world’s no. 1 spot.

Alas, poor single-fister. But what can we spectators do? It’s what happens out in the middle that matters. That’s where you find the crucible of sporting evolution.