At the age of 41, Tom Brady is on the verge of a record sixth Super Bowl triumph. Photo / Getty Images
In a week when Roger Federer and Serena Williams have betrayed signs of wear on their 37-year-old physiques, Tom Brady has kept rolling into his ninth Super Bowl, as reliably as the Mississippi River.
At 41, Tom Terrific - he also answers to TB12, California Cool or, more obliquely, The Pharaoh - has, in his 19-year career at the New England Patriots, reached American football's greatest stage more times than any of the NFL's 31 other franchises.
No doubt it helped, as motivational shtick, that Julian Edelman, Brady's first-choice wide receiver, spent much of Monday's victory over the Kansas City Chiefs screaming at him: "You're too old!"
Using any normal logic, Brady should be pensionable by now. He inhabits a sport where a player's average competitive life spans just 18 months, but he remains somehow imperishable, a throwback to a time when Al Gore still stood a chance of becoming US President and when Facebook had yet even to reach Mark Zuckerberg's dorm room.
To Patriots owner Robert Kraft, Brady has changed little from the gangly jock that he plucked from the University of Michigan as a sixth-round draft pick in April 2000.
"He's still the same guy," said a misty-eyed Kraft. "That same skinny beanpole."
Well, apart from the endorsements from Under Armour and Ugg Boots, the salary that peaked at US$28 million ($41.3 million) a year, the penthouse in Manhattan and the marriage to Gisele Bundchen, at her zenith the highest-earning supermodel on the planet.
By rights, Brady, with nothing left to prove as the embodiment of the American dream, should be content catching a few breakers in Malibu or sipping his morning macchiatos in Tribeca.
Instead, he continues strapping on the body armour, redefining the parameters of athletic twilight. A year ago, it had looked as if Brady would retreat into the shadows, after a painful Super Bowl defeat by the Philadelphia Eagles pointed to the gradual ebbing of his powers.
Already, he was one of only two players ever to lift the Vince Lombardi Trophy five times, alongside former defensive end Charles Haley, and the sole figure to do it all with the same team.
And yet a voice in his head kept insisting he could make the gulf to the chasing pack wider still. So, here we are, on the cusp of Super Bowl ring No6 and a date with the Los Angeles Rams, whose head coach, Sean McVay, was just 14 when Brady sealed his first title - against, you guessed it, the Rams.
It is not unprecedented for quarterbacks to press on well into their fifth decade.
Brett Favre, of the Green Bay Packers, hung up the cleats at 41, becoming such a semi-deity in Wisconsin that one joke was that his jersey number, four, should be not just retired but withdrawn from the entire numerical system. The difference is that Brady, so far into his dotage, has not just reclaimed but enhanced his pre-eminence.
By advancing to the Super Bowl in three straight seasons - even at his apex, from 2002 to 2005, he had to settle for three in four - he arguably deserves to be given two plaques at his eventual Hall of Fame induction in Canton, Ohio.
Brady, by his own admission, is not the most natural athlete. When it comes to dead-lifts or the 40-yard dash, most of his team-mates would leave him for dust. Where he is unparalleled is in strategic acumen, not to mention poise under pressure. Against the Chiefs, the Patriots were four points down with 40 seconds to go, only for Brady, with his usual extrasensory perception, to spot the run of Rex Burkhead and hand off for a crucial touchdown. Sure enough, in overtime, the same combination yielded a momentous New England triumph.
"If there is a clutch gene," as Edelman said of Brady, "then he has it."
Is Brady simply too good to be true? Many eyebrows have been raised over his relationship with personal trainer Alex Guerrero, who has made it his niche to increase longevity via extreme methods.
Under the guru's supervision, Brady has committed to drinking almost eight litres of water a day, such a prodigious level of hydration that he argues he can never be sunburned.
But there are shadier episodes in Guerrero's past. In 2004, he hawked a nutritional supplement whose stated properties included curing arthritis, which the Federal Trade Commission ruled had no basis in fact. Treatments that Brady cites as the elixir of life are dismissed by sceptics as quackery.
To his detractors, Brady also carries an indelible taint from his alleged role in "Deflategate", the 2015 scandal in which the quarterback was accused of the deliberate deflating of footballs. He denied any involvement but accepted a four-game suspension.
Even these black marks, though, have to be set within a far richer tapestry. Brady, in his 20th year as a professional sportsman, is hitting a degree of sustained excellence that perhaps shades even Federer's.
On the tennis court, Federer does not have to fear any confrontations with an onrushing linebacker whose only thought is to floor him with the force of a battering ram. And, yet, somehow Brady braves the blows, mends the scars, and returns to do it all over again. It appears as if he is chasing that rarest of sporting commodities: the perfect ending.
When he emerges for the 53rd Super Bowl in Atlanta in eight days, few could possibly begrudge him the pleasure.