How the torch was passed: Eerie 16-year echoes of Djoker's first ...

Science will tell you that an echo cannot last forever; that eventually, it’ll run out of energy.

But that’s untrue. We just saw one return after 16 years.

Jannik Sinner’s stunning Australian Open semi-final win over 10-time champion Novak Djokovic marks a potential changing of the guard in tennis; the 22-year-old stopping the greatest performer we’ve ever seen at Melbourne Park, and in dominant fashion.

But for many, it brought back memories of 2008, when a certain young star on the rise broke the stranglehold of the world No.1 before claiming his maiden slam title.

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In that year’s top-half semi-final it was Roger Federer, winner of 12 of the previous 18 slams he attended and the No.1 seed, against the upstart No.3 seed Novak Djokovic, whose best career performance was a slam final the previous year (where he lost to Federer).

Djokovic, staggeringly, won in straight sets, including a third-set tiebreak. He then downed Frenchman Jo-Wilfried Tsonga in the final to claim his first of 24 slam titles.

In this year’s top-half semi-final it was Novak Djokovic, winner of 12 of the previous 19 slams he attended and the No.1 seed, against the upstart No.4 seed Jannik Sinner, whose best career performance was a slam semi-final the previous year (where he lost to Djokovic).

Sinner almost repeated the feat exactly, leading two sets and holding match point in the third-set tiebreak, before claiming victory in four.

And he may almost repeat the opponent, as he can face Daniil Medvedev - who is Russian but moved to France as a teenager - to win his first slam title (if Medvedev beats Alex Zverev in the other semi-final).

Djokovic was aged just 20 when he won his first slam. Sinner would be slightly behind the greatest pace in tennis history, aged 22, if he triumphs on Sunday. So, again, another category where Djokovic is just ahead. But we’re also comparing the greatest player of all-time with a kid who can barely rent a car.

The significance of Friday’s passing of the torch cannot be overstated, even if Sinner falls in his first grand slam final (which many of the greats, including Djokovic, did).

He has arrived. And, along with Carlos Alcaraz’s Wimbledon triumph over Djokovic, it’s clear the tennis world has finally found the players good enough to sit on his throne.

That’s not to say he will abdicate it. Djokovic can, and likely will, still win a slam or two this year.

Change just takes a lot longer than you think.