The defeat of Rafael Nadal and Novak Djokovic, two of the big stars who were expected to reach at least the semi-finals of the Australian Open and the former’s subsequent rant against the heavy workload on top players holds out worrying signs for the world of tennis.

The recurring injuries to Nadal and Djokovic are not a good sign. The second and more important point is that these two are among the quartet — the others being Roger Federer and Andy Murray — who have won 50 of the last 55 Grand Slams showing how they have dominated men’s tennis.

Of this quartet, three are rather seriously injured and a return to top physical fitness can be ruled out.

Nadal’s rant against the tour is also significant.

“It’s not the right moment to say for me, but somebody who is running the tour should think a little bit about what’s going on,” he said.

The same emotions were expressed by the others but it must be remembered that when they were fully fit all of them had supported the tour organisation.

Nadal has lost in Grand Slams earlier as well, but in none of the other defeats was there the echo of dismal forebodings.

While Murray too will return to the tour, his long term continuation is suspect, according to experts in Melbourne.

In the case of Djokovic who was shunted out of the Australian Open by South Korean upstart Hyeon Chung who has now reached the semi-final, the injury is to his elbow, a situation popularly known as the tennis elbow which recurs off and on and for which there is no complete cure.

Worse for Djokovic, there is clearly a decline in his game starting from mid-2016. In 2016-2017 he lost nine games, six of which were them to players ranked outside the top ten.

The massive straight-sets defeat (7-6, 7-5, 7-5) which Chung inflicted on him at the cavernous Rod Laver arena, falls clearly in that category.

What this seems to show is that his game has been declining in various aspects and neither his new team members Andre Agassi and Radek Stepanek nor his adjustments in his game seem to help.

The over 10th ranked players he has lost to in just over a year are Sam Querry (ranked 41 at Wimbledon), Martin Juan Del Potro (now top ten but at Rio Olympics was ranked 141 due to injury absence) Roberto Batusta Agut (ranked 19 at the Shanghai Masters) Denis Istomin (117 Aus Open), two loses to Nick Krygios (17, Mexico and Indian Wells) and Jiri Vesely of the Czech Republic.

So the surrender of Djokovic is in keeping with a clearly discernible pattern of unpredictable defeats. Why does it happen to a player who is clearly among the top five even now in terms of his game and stature.

Are the flaws showing? There is no doubt that the domination of the quartet is ending. It is a natural evolution of course. But the problem here is that men’s tennis revolves round these four and a few others.

The others who are doing well on the tour do not have the marketing potential as yet to draw in the big money to the tour. And with players grumbling about the pay, the problems for the ATP tour in the coming months are many.