Citroen takes blame for oil pump issue which caused Loeb's retirement

That is the uncompromising verdict of team principal Olivier Quesnel, who said the team had made a rare mistake in their preparation.

"Sebastien had a new engine in France," said Quesnel. "I think we did a mistake when building the engine. It didn't happen in more than 10 years but it happened this time and it was Rallye de France in Sebastien Loeb's car. We are very sorry but this is rallying."

Loeb retired after the third stage of the rally when he noticed the oil pressure light come on his DS3 WRC. After switching off the anti-lag system he then sensed the engine losing power and chose to switch it off.

"It's the first time that I've had an engine failure during a rally since 2003 or 2004," said Loeb. "It's happened during tests before, but in competition it's very rare.

"We think it was the oil pump that failed, so there was nothing we could do. Obviously this opens up the championship again.

"I've always said that winning rallies was never easy and winning championships was even harder. A zero score can put everything into question...but for the moment I'm not thinking about that."

Loeb will be consoled by his track record in Spain, the next round of the championship in two weeks time, having won the rally six times previously.