Lewis Hamilton insists he "couldn't care less" that Nico Rosberg has stolen an early march in the battle for this season's Formula One championship.

Rosberg has extended his lead over Hamilton to 17 points by following up his triumph at the curtain-raiser in Melbourne with his second victory of the campaign in Bahrain on Sunday.

The German, winner of the last five grands prix - a streak which stretches back to last season - benefited from a sluggish start by Hamilton to claim the 16th victory of his career. Hamilton sustained damage in a first-corner collision with Valtteri Bottas before nursing his Mercedes home to finish third.

The Briton, who last tasted victory at October's United States Grand Prix, the scene of his third world championship, said: "I couldn't care less if he's won the last five, it's the last two that matter .

"If you win consecutively in the season that's something, but five over two seasons, for me that doesn't psychologically mean anything."

Making reference to Muhammad Ali's famous world heavyweight title fight against George Foreman in 1974 in which Ali soaked up pressure in the opening rounds before knocking his rival out in the eighth, Hamilton added: "You can't win them all. Not that this is the same, but Muhammad Ali with that Rumble in the Jungle....he got the dude to believe that he was winning and he didn't. So anything can happen.

"This is a psychological game, for sure. It is a battle. I guess with age and experience, I'm in the most solid place I've ever been psychologically. There's very little if anything that can penetrate that."

Hamilton secured pole position with a record-breaking lap under the lights in Bahrain to start from the front for the second race in succession.

But, as in Melbourne, a poor getaway from the world champion saw him slip back through the field.

"I feel really positive generally, even though we have lost the first two races," Hamilton, 31, added.

"I've had two poles and we are going to get more. There's no real flaws in our procedure and how we are working. It will start getting better.

"Nobody likes losing and of course all my guys back at the factory work so hard. My engineers did such a fantastic job and we could have easily converted that to a win. We had the pace. We didn't win and we all feel the pain. But I told them there's a long way to go."

Rosberg moved onto 16 career wins, equalling Sir Stirling Moss' rather unwanted long-standing record as the driver who has won the most races without winning a title.

"I am happy to have finally won the Bahrain race," said Rosberg.

"I had an awesome start, it felt like a rocket launch. It was perfect and that made the race."