Hamilton keeping fit without trainer in 2017

Lewis Hamilton says he is looking forward to battling Sebastian Vettel for the world championship in 2017.

Since 2014, with Mercedes basically alone at the front of the field, Hamilton’s battle were confined to an acrimonious inter-team scrap with Nico Rosberg.

So with Rosberg retired and Ferrari’s Vettel now in the fray, Hamilton was asked if he thought the German would be a better challenger.

"Definitely. Definitely," he is quoted by Die Welt newspaper.

Hamilton’s answer might be interpreted as a slight against Rosberg, who hung up his helmet immediately after winning the 2017 title.

"This year we will see the best against the best," the Briton said. "The best drivers at the top."

However, some might question Hamilton’s hunger in comparison to quadruple world champion Vettel, with the Mercedes driver heading off for ’snowboarding’ in the desert this week rather than staying in Asia ahead of next weekend’s Chinese grand prix.

But Hamilton insists: "Definitely my discipline has gone up. With my diet, my sleep, all these things."

He revealed that although the cars have got much faster for 2017, he is now doing his physical training by himself — without the aid of a trainer.

"That was the challenge I set myself — could I have the motivation to do it myself? I’ll need to keep working, because there are going to be some really tough races this year," said Hamilton.