SOCHI (Russia) (REUTERS) - Nico Rosberg's fading Formula One title hopes suffered another massive blow on Sunday when the German retired his Mercedes from the Russian Grand Prix after leading from pole position.

The German pole holder, who had started the race 48 points adrift of double world champion Lewis Hamilton with 100 points remaining to be won after Sochi, had complained of a broken throttle pedal.

Hamilton, who had started second on the grid, went on to secure his ninth victory of the season. The result leaves the Briton 66 points clear of German Sebastian Vettel, who finished second and is now also second in the drivers' standings.

Hamilton is now 73 points ahead of his team-mate and in line to secure his third world crown in Texas in two weeks' time.

"Your team-mate has retired. Let us focus on this race," Hamilton, who passed Rosberg on the sixth lap, was told over the team radio after the German pulled into the pits and stepped out of the car at the end of Lap 7.

Rosberg put a brave face on his second retirement of the season and second in four races.

"F1 is pretty incredible sometimes how tough it is," he told the BBC. "After a great start, leading the race and feeling confident. Straight after the safety car, the pedal broke. It was quite dangerous. Definitely not a nice way to end the day.

"The championship is more difficult of course but I am never going to win a championship like that when normal things break. But I will come back, keep pushing, keep attacking and try to win in Texas."

Mexican Sergio Perez put his Force India on the podium too, after Valterri Bottas lost third place late on after Ferrari's Kimi Raikkonen crashed into his Williams car.