BARCELONA (REUTERS) - Formula One championship leader Nico Rosberg's hopes of an eighth successive win, and fifth of the season, disappeared on Sunday after a collision with Mercedes team-mate Lewis Hamilton on the opening lap of the Spanish Grand Prix.

The British triple world champion had started on pole, with the German alongside on the front row at the Circuit de Catalunya.

The German passed Hamilton round the outside of Turn 1 and the Briton was then squeezed onto the grass as he tried to regain the lead at Turn 3. His car skewed sideways and hit Rosberg's, with both drivers ending up in the gravel and the safety car was deployed.

Watching Daimler chief executive Dieter Zetsche shook his head in dismay, while Hamilton threw his steering wheel out of the car. With both Mercedes drivers out of the race, Rosberg (100 points) still leads the Briton by 43 points after five of the 17 rounds.

With nearly two-thirds of the 66-lap race gone, Australian Daniel Ricciardo, who started third on the grid, leads in his Red Bull.