Hamilton beleives Ferrari is a month ahead on development path

The winter tests saw Ferrari top Mercedes on the timesheets. These sessions don't determine where they'll finish at the end of the year, but Hamilton believes the early Ferrari success is because they started work a lot earlier.

Hamilton, now a five-time world champion, suggests last year's end of season lull from Ferrari allowed them to start development earlier.

"Obviously during the year you have a huge group of people who are working towards winning the world championship and if you are not looking like you are winning the world championship, out of worry you might pull some of the team off earlier," Hamilton told Motorsport.

"So most likely they started developing this car a month at least earlier than us maybe, whereas we were pushing to win the world title, which we did."

The Brit was asked how this could affect Mercedes in the long run. As last year proved, the Silver Arrows love a good fight.

"We don't mind the challenge. We will fight. It just means we have to work harder. But I am really really proud of what our team has done to get us here today," he added.

See also: Hamilton says Mercedes has a serious hill to climb.