South African Giniel De Villiers stretched his overall lead in the Dakar Rally on Sunday after Volkswagen team mate Carlos Sainz was slowed by power steering problems.

De Villiers, last year's runner-up, won the eighth 589km stage between Atar and Tichit in Mauritania to lead Mitsubishi's former winner Stephane Peterhansel of France by 31 minutes and 13 seconds.

Double world rally champion Sainz, the leader before Friday's shortened seventh stage, slipped to fourth overall after driving for almost 300km through the desert with no power steering.

Mitsubishi's 2006 winner Luc Alphand of France moved up to third place, despite twice getting stuck in the dunes.

"Of course it's good that we stole some time from Mitsubishi," De Villiers told the rally Web site (www.dakar.com).

"We will have to do the same tomorrow. In the overall rankings, 30 minutes does not mean that much. We saw today with Carlos Sainz that problems can be costly real quick."

In the bikes category, Spaniard and champion Marc Coma extended his lead to 54 minutes on a KTM ahead of Frenchman Cyril Despres, the 2005 winner.

Spain's Isidre Esteve, Coma's big rival in the earlier stages, broke the gearbox on his KTM just as Despres had earlier on in the rally.

"It's a pity for Isidre because the battle was interesting and it was providing a great show," said Coma. "But nothing is settled yet."

Frenchman Patrice Carillon surprised officials when he turned up on foot at the day's third checkpoint after running out of fuel. He picked up a few litres and turned around to rejoin his motorcycle down the road.

Monday's ninth stage is from Tichit to Nema in Mali.