Former world champion Jacques Villeneuve thinks Lewis Hamilton acted like "a spoilt child" after winning the 2015 title.
Hamilton failed to beat Mercedes team-mate Nico Rosberg in qualifying or the race in Mexico, Brazil or Abu Dhabi despite wrapping up the championship in Austin. During that time he complained changes to the Mercedes W06 after Singapore had shifted momentum to Rosberg, while suggesting his team was going to special measures to keep his German team-mate happy after losing the championship.
The negativity between both Mercedes drivers at the end of the season prompted Toto Wolff to warn the team would consider a line-up change if it continues into 2016. Villeneuve, who won the title with Williams in 1997, thinks the final races of the season highlighted "a very negative side" of Hamilton's character.
"After [Rosberg] lost the championship, it looks like something changed in him," Villeneuve told German publication Motorsport-Magazin. "I don't know for sure but he became a killer. Lewis, however, reacted pretty badly and showed a very negative side of his character.
"He showed that he cannot be humble. He has secured three world championships but could not rejoice and behaved like a spoilt child whose toys had been taken away from him. He has not acted like a great champion."
After Abu Dhabi, Wolff said Mercedes would look into why Hamilton's form dropped off at the end of the season. Villeneuve does not think it is wise for Hamilton to make such an issue of changes to the car after such a dominant season.
"He is the one who sits in the car. He is the one who works with his engineer. It is up to him. Whatever kind of a setup they have, it seems to suit Nico better, but maybe that's because Nico has worked.
"If that is the case, then perhaps Lewis was not as superior as he appeared to be this year. He just had a better setup. That's why he should be careful when he says things like that."