Former F1 tester Bas Leinders has said that he thinks Lewis Hamilton lost focus earlier in 2016.
In Abu Dhabi, Hamilton has hinted that his likely title defeat to Nico Rosberg on Sunday would be due to an early-season engineer switch, and poorer reliability.
However, Leinders, a Minardi test driver in 2004, said that Rosberg would "definitely" be a deserved world champion if crowned late on Sunday.
"Critics might say that he has only become champion through Hamilton's misfortune, but that's not true," he told Belgium's Sporza.
"OK, Hamilton had mechanical failures but so did Rosberg.
"It is more about how Hamilton tackled his season. In the middle of the season he was too preoccupied with his friends in LA and Hollywood. That certainly had an impact."
Leinders also hit out at the idea that Hamilton was clearly the best driver of 2016.
"Hamilton was not the best driver of the season," he insisted. "It was Max Verstappen. What he has done was phenomenal.
"If he gets into the right car, he will certainly be world champion."
Hamilton will start on pole for tomorrow's race.
