Citroen's Loeb, chasing his eighth championship in a row and with an eight-point lead, took over at the front from his Finnish rival.

"It's over for sure," Hirvonen, who is allowed to rejoin the rally on Saturday but may not able to due to damage to the car's engine, told the official wrc.com website of his bid for a first title.

"I have to thank the team for a really good effort and all the help. Unfortunately we have to look to the future and see what we can do." Loeb, however, was not ready to celebrate just yet.

"For us the situation is a bit less under pressure now than it was a few stages ago because it was a big battle with Mikko. Now the situation is a bit easier but still it's not finished," the Frenchman said on wrc.com.

"We have to check exactly what is the situation but if Mikko will not restart then we are world champion. But if there is a possibility that he can come back in the points then we have to look at it a bit differently." Hirvonen, who had taken the overall lead earlier in the day from Loeb, had to pull over on the road while attempting to nurse the Ford back to the service area in Builth Wells in central Wales.

The Finn's Fiesta had hit a submerged branch on the seventh, Dyfnant, stage and damaged the car's radiator.

"There was a big slide and the rear touched the bank," he reported.

"I spun and it pulled the front of the car into a bank where there was a tree stump. The wood came through the radiator. There was no real damage but we lost all the water in the engine. We carried on for five-six km but that was it." Even before he stopped, Hirvonen had lost almost four minutes to Loeb, the overnight leader after three stages on Thursday, because of the incident.

"It's devastating to go out in an incredible battle with Sebastien Loeb," said Ford team boss Malcolm Wilson. "We will try to fix the car but it does look like there's too much damage to the engine.

"It's a huge disappointment for the whole team after getting back into the championship fight again and then sadly losing it on the first day of the event."