Nico Rosberg insists he won't change his approach in the final four races, even though a retirement from the Russian Grand Prix has all but eliminated him from the 2015 F1 title battle.

The German was looking good for a potential fourth win of the season in Sochi having taken an early lead from pole position, but a problem with the throttle pedal - which had shifted and was staying open under braking - in the early laps would force him to retire on lap five.

Already faced with a 48 point deficit to Lewis Hamilton coming into the weekend, not only has the Englishman's ninth win of the year put him 73 points clear with a maximum of 100 points available from the final four races, he is also now behind Sebastian Vettel in the standings.

Accepting he needs to be 'realistic' about his title aspirations, Rosberg nonetheless says he won't change his approach in the last races.

"We will just have to be realistic now - it is a lot of points. It doesn't change my approach, I'm still pushing to the maximum and being committed. Going for it mentally, it doesn't change much. Disappointing of course because I was looking to close the gap. Anyway, I will go to the next race and I want to win."

When asked whether he would intervene should the title battle come down to a tussle between Hamilton and Ferrari's Vettel, Rosberg replied that he didn't want to 'go into it' now.

Reflecting on the reason for his exit, Rosberg says the movement from the pedal would compromise his seating position, making it difficult for him to steer.

"The change happened in the safety car period and from then on I couldn't come off the throttle anymore. I was doing all the corners with the throttle on and then eventually it was so that I couldn't get round the corner anymore.

"It was one big step under the safety car that it came towards me and then another smaller one afterwards which meant that was the end. I was trying to take my leg off the pedal, but then my knee would come up and I couldn't steer. The throttle is never a nice thing [to go wrong], especially when it is sticking."