World champion Sebastian Vettel's hopes of becoming the first repeat winner of the Formula One season vanished on Sunday when he retired from the European Grand Prix in Valencia while leading from pole position.

The German was on course for a hat-trick of wins in the Spanish port city, after winning in 2010 and 2011, when his Red Bull suddenly lost power after racing had restarted following a safety car period.

The champion stepped out of his stricken car and angrily threw a glove at the wall while Red Bull designer and technical head Adrian Newey, watching on the team pit wall, buried his head in his hands in despair.

Vettel left Ferrari's Fernando Alonso in first place, to the delight of the home fans.

Frenchman Romain Grosjean, who had hoped to become the eighth different winner in eight races, then retired when his Lotus suffered an alternator problem while challenging the Ferrari for the lead.