Change of Serb Djokovic faced with hardest call of all as contenders line up to be next No 1

The greatest light-heavyweight of them all, Archie Moore, was 47 and still champion of the world when he explained better than anyone - before or since - why so many sporting immortals refuse to go gently into the good night.

At this point the siren call of family and the easy life was deafening. Moore also knew his wife yearned for him to retire, and he adored spending time with his young daughters "lest they forget that love and life go hand in hand". Yet the mere thought of fighters half his age wanting his belts stirred the warrior in him once more.

"I'm still the old mongoose in there trying to outwit and outhit the younger guys," he said. "I'm like the drunk in the bar who wants one more for the road. I want one more knockout to add to my record and just one more after that. Some people say it's great when a man retires undefeated. But a champion should fight to the finish and go out with his hands cocked just as he came in. It's the proper exit and I think it may be mine."

And so on Moore went, for another three years, taking on all-comers including a young Muhammad Ali, before retiring at 50 after his 186th career victory.

I thought of Moore's words last week while watching an unusually subdued Novak Djokovic endure a shock defeat against the world No 123, Luca Nardi, at Indian Wells. And again while seeing the two young contenders for his No 1 crown, Jannik Sinner and Carlos Alcaraz, duke it out on a stormy desert Saturday night.