The enduring mystery of Lewis Hamilton’s late season slump that turned the championship countdown into a showcase for his teammate Nico Rosberg is a riddle likely to be clear only to himself.

Theories as to Hamilton’s decline, outside his own orbit of sealed-lips privacy, abound among baffled onlookers and close compatriots alike.

Regardless, Rosberg eagerly and gratefully cashed in with his first-ever hat-trick of victories and the Mercedes bosses, whether they knew as a matter of fact or merely suspected a reason for his downfall, refused to highlight Hamilton’s problem.

An interesting and objective opinion was offered by Ron Dennis, the bluntly outspoken McLaren overlord who was the original influence on Hamilton’s career and who steered the 30-year-old along the path of success before he split to drive for Mercedes.

There had been a telling admission from Hamilton that he had been overtaken by a whirlwind of partying since his third title clincher and he certainly launched himself onto a TransAtlantic trekking marathon to the USA from his Monaco base in his private jet.

Partying with celebrity chums, movie stars and rap idols, he admitted, took its toll and he was lucky to escape without a scratch when he crashed his pounds 1.5 million (Dh8.3 million) Pagani Zonda supercar into three parked vehicles at 3.30am in Monaco.

Dennis, a dictatorial character famed for his strict codes of behaviour among his staff and never a man to hold back on an opinion, however hurtful or candid, opened up on Hamilton like this:

“If he was still at McLaren he would not be behaving the way he is because he would not be allowed to.

“He is shaking off some of the chains he did not want to have.”

Hamilton agrees that since opting out of his McLaren career to switch to Mercedes in 2013 he has felt freer than he ever did under Dennis’s spartan regime.

Off the Hamilton scene, too, is his father and one-time manager Anthony, once a constant by his son’s side but now an absentee from the grand prix environment after a split in their tie-up business and parent-wise.

Dennis, who had nurtured Hamilton from being a 13-year-old karter onto the full-blown Formula One stage and then as a world champion in 2008, only his second year in the top flight, adds: “I do not now approve of everything he does or says.

“When he raced for McLaren it was an interesting experience and it was not completely smooth and harmonious.

“Nevertheless, great athletes are great because of the sacrifices they have to make. And sometimes those sacrifices are in a very formative part of their childhood — so they do not always emerge with the right social process or behaviour or tendencies that you like.”

After securing his third title, equalling his hero Ayrton Senna, and ranking himself among the grand prix greats, Hamilton buzzed: “This is the greatest moment of my life. I cannot believe I am the champion for the third time.”

From that moment on his grand prix chase went mysteriously into reverse.

What caused it is what we all want to know. And can we...and his anxious Mercedes team...be sure he won’t still be going backwards in next season’s series?

— The author is an expert on motorsport