Valtteri Bottas says his surge of form in 2019 is due to his improved psychological approach to Formula 1.

The Finn was devastated to be roundly beaten by Mercedes teammate Lewis Hamilton in 2018.

Hamilton claims a new engineer has helped Bottas so far this year, but Bottas says it is about many "little details".

"I worked on the weaknesses in my driving and the setup, and my beard of course," he smiled to El Mundo Deportivo newspaper in Barcelona.

"I think it's more a question of attitude, because in every sport it is also about the mental side. More mental than physical," Bottas said. "It's about what is in here," he added, pointing to his head.

But the 29-year-old said he has achieved it without the help of a psychological coach.

"No. There is no one who knows me better than myself," Bottas insisted. "I know what I need to do to perform."

For instance, he says he is not even feeling the pressure in 2019, a season in which his contract expires and Esteban Ocon is waiting in the wings.

"I do not have any pressure this year," he said. "And I will not have it, whatever happens.

"For me the current situation is a dream come true, fighting for the championship and having such a tight battle with Lewis Hamilton.

"I do not have pressure, I'm just trying to enjoy it and the results come.

"The end of last season was pretty hard mentally. It was a very difficult time for me.

"At the end of the year, I took my time to feel good again and start the new season with the right attitude."

One perception is that Bottas has dropped the 'nice guy' approach, in which many earlier saw him as a supportive driver for team number 1 Hamilton.

"You always have to have respect and think about the team, but you also have to think about yourself and your career. So far I worked thinking about the long term but this year I am looking more short term," he said.

And he is confident his relationship with Hamilton will not break down, as the Briton's did with Nico Rosberg a few years ago.

"If we reach the end of the year close and fighting for the title, the closer we are the harder it will be," said Bottas.

"But we both know the situation, we are adults and we both want to win."

Hamilton has announced that he was too "friendly" to Bottas at the start of the race in Baku, but the Finn says he can also be more aggressive.

"I think we were very clean in Baku," he said. "I could also have been more aggressive at the start but you have to always think about the good of the team as well."