Sebastien Loeb was forced to pull out of the Dakar Rally after a back injury suffered by his co-driver in a disastrous fifth stage won by defending champion Stephane Peterhansel on Wednesday.

As Peterhansel took another important step towards his 14th Dakar title Loeb's dream of winning his first Dakar was left in tatters after his car twice ran into early sand trouble on the run from San Juan de Marcona to Arequipe in Peru.

The French ace's hopes of adding a Dakar to his nine world rally championship crowns at the third attempt had appeared encouraging after climbing to second in the standings with success on Tuesday's fourth stage.

But instead he was left rebooking his flight home after his Peugeot became stuck in the dunes twice, with a truck having to help him out of a sand hole, costing him almost three hours.

Yet it was an injury suffered by co-driver Daniel Elena as they descended a dune that forced Loeb to bring a premature end to his 2018 Dakar 10 days before the finish in Cordoba, Argentina.

"He screams as soon as I go over 30 km/h, I can't see how we can go on like this", explained Loeb, second last year.

He added later: "It went badly, the dunes are too soft, we did not see the hole, we hit it hard ... It's over, Daniel is bad, but he'll be okay. It's so soft, without the (assistance) truck, we wouldn't have got out," Loeb told France Television.

After his fourth stage win on Tuesday Loeb was placed seven minutes second to Peterhansel in another Peugeot.

France's 'Mr Dakar' has won the car title seven times with a further six titles on two wheels, the first coming way back in 1991.

The 52-year-old saw off the Toyotas of Bernhard ten Brinke and Giniel de Villiers to lead his Spanish teammate Carlos Sainz by over half an hour overall.

Third-placed ten Brinke is a massive 1hr 15min adrift.

Loeb's defection followed on from that earlier Wednesday of Andre Villas-Boas, the former Chelsea and Tottenham manager who had to pull out with a bad back, his Toyota team reported.

Honda's Spanish rider Joan Barreda Hort won the motorbike stage with Yamaha's Adrien van Beveren retaining the overall lead.

Barreda covered the 264 kilometre timed section in three hours 19 minutes 42 seconds to cross the line over 10mins up on Matthias Walkner on a KTM and Kevin Benavides (Honda).

France's van Beveren took fifth to hold a slim one minute cushion over Benavides with Walkner 1min 14sec off the pace.