It happens to every player when they accelerate past the wrong side of 30. Suddenly the legs are heavier. The pace starts to go, younger opponents whizz by as though they are riding on invisible motorbikes and the body begins to rebel.
The old magic starts to disappear and naysayers line up to say that you’re in the throes of irreversible decline. There are two options. Either you accept the inevitable and learn to live with the surprisingly welcome human reality of growing old. Or you rebel.
Cristiano Ronaldo chose the latter. Bowing down to time simply is not his style, not when there are so many goals still to be scored, awards to win and mirrors to glance at admiringly, and while he might not be as blisteringly quick as he was a year or two ago, Ronaldo shows no sign of slowing down in other ways.
Still so driven, so focused, so utterly and unforgivingly relentless, Ronaldo did not need long to leave his mark on Atlético Madrid at the start of this Champions League semi-final.
There were only 10 minutes on the clock when Casemiro sent a bouncing cross into the middle from the right and Ronaldo towered over Stefan Savic, who has matured into a forceful centre-back since his torrid spell at Manchester City, and thumped a low header past the Atlético goalkeeper Jan Oblak.
Even a team as tough and resolute as Diego Simeone’s Atlético were powerless to stop him and Ronaldo’s early goal gave Real control. His second strike, a brutal volley from 18 yards late in the second half, gave Zinedine Zidane’s team precious breathing space.
His third with four minutes to go means that they are within touching distance of next month’s final in Cardiff.
Another big match, another Ronaldo hat-trick. It is strange, this eagerness to doubt him. More than anything else, it feels like a dangerous game to write him off bearing in mind the astonishing consistency of his cold ruthlessness in front of goal.
Booed by his own fans during Real's previous Champions League outing at the Bernabéu against Bayern Munich, he shrugged his impossibly broad shoulders and promptly made the most of a couple of generous offside decisions by scoring the hat-trick that sent the German side tumbling out of Europe. It wasn't a bad night's work for a busted flush.
The best footballers have always been capable of tweaking and refining their games as the years pass by. Those who fail to adapt struggle to replicate former glories, so criticising Ronaldo for not flying down the wing and tying full-backs up in knots misses the central point.
Real have Marco Asensio, a jinking 21-year-old Spaniard, to weave and scheme on the flanks these days. Marcelo provides wonderful thrust from left-back. Instead of using up his energy on needless endeavours, Ronaldo lurks in other areas of the pitch. He has become a deluxe poacher, an elite goalscorer, and he does his job with devastating efficiency.
There were occasions when Ronaldo crept into the wide areas. Shortly after his first goal, he teased Atlético on the left, his feet twinkling, and he crossed for Karim Benzema to hook his effort just wide. Early in the second half, Ronaldo ripped past Diego Godín on the right and tried to set up Benzema once again.
But his best work is done in the penalty box. Goals are his elixir. Ronaldo began the game by walloping over from 25 yards when he might have passed to a team-mate in a better position.
He is not as pure a player as Lionel Messi, who bends matches to his will
He did not let that put him off. Instead he kept coming back for more, forcing Oblak to make a superb save with a downward header.
Ronaldo drifted out of the game for a while. He is not as pure a player as Lionel Messi, who bends matches to his will for Barcelona. But he was just biding his time. The 32-year-old's second goal was a swaggering show of force and it took Real closer to their third Champions League final in the past four years.
The second leg is likely to be a formality at the Vicente Calderón. Real are excellent value for the 3-0 lead that they will take across the capital next Wednesday. It was a complete performance from Zidane’s men, who overwhelmed Atlético in midfield and restricted them to few clear chances.
An away goal was never on the cards for Simeone's team, save for the moment when Kévin Gameiro burst behind Sergio Ramos and Raphaël Varane in the first half.
With Ronaldo in this mood, Real will take some stopping. There were no jeers at the Bernabéu this time.