Lewis Hamilton feels he has mental strength to defend F1 title

Lewis Hamilton's second world title, in 2014, came six years after his first

Lewis Hamilton feels he is "stronger than ever" thanks to the "impenetrable" mental attitude he fostered in becoming world champion last year.

The Briton said he drew strength from winning the title amid a fierce rivalry with Mercedes team-mate Nico Rosberg.

Hamilton added that he would not let his break-up with Nicole Scherzinger affect him ahead of next weekend's season-opening Australian Grand Prix.

"I developed a mental attitude I would like to say was impenetrable," he said.

"Of course, in previous years it has been the case where it [a break up] has affected my life in general.

"But I feel I still carry that kind of mentality from last year - and while it's not been easy, having been in this position before I feel stronger than ever, so I don't feel it's going to be a problem."

Hamilton said the collision with Rosberg during the Belgium Grand Prix at Spa last season that strengthened his resolve.

Lewis Hamilton won 11 F1 races in 2014

Speaking to the Observer, Hamilton said: "After Spa I thought 'I'm going to turn this up. I'm going to have to turn this up. This means war.' After Spa I had a different approach."

He described becoming world champion for a second time as "like a warmth in your heart that you carry", but said there is "no less pressure" going into the new season.

The Briton added: "I didn't arrive at the tests thinking 'OK, I'm world champion.' I'm thinking 'I've got to do everything again and I've got to do it better than I did before because I know that everyone else will have taken a step.'"

Hamilton is close to signing a new contract with Mercedes, having conducted negotiations himself after leaving Simon Fuller's management company XIX last year.

He said: "It's been an experience. Learning something new and experiencing something like this, I'm glad I've done it. It's a very, very nerve-racking kind of experience, but I just tried to do the best job I possibly could.

"Hopefully we're in the final stages. I don't really know what the timeline is. We're not rushing, but we're very much in the last stages of it."