Sochi, Russia: Sebastian Vettel will start Sunday's Russian Grand Prix with a five place grid penalty after his Ferrari team on Friday decided to change his car's gearbox.

Sebastian Vettel. Pic/AFP

The four-time world champion had earlier stopped out on track during second practice when his car failed due to an electrical problem. He was second fastest in the afternoon session behind defending three time world champion Lewis Hamilton of Mercedes.

Vettel has admitted he and Ferrari are under pressure to improve results after seeing Hamilton's team-mate Nico Rosberg reel off three season-opening wins to lead the title race by 36 points.

Hamilton is also using a new gearbox this weekend, but this follows him replacing one at the Chinese Grand Prix where he took a grid penalty.

He has no grid penalty for this race.