Dakar Rally leader Nasser Al-Attiyah took Wednesday's fourth stage in Riyadh after Saudi driver Yazeed Al-Rajhi was caught out by a speeding penalty.

The home hope led the timings after the 465 kilometre trek across the desert from Qaisumah.

But a two minute sanction dropped him down to fifth, with Al-Attiyah handed the stage to add to his success in the prologue and first stage.

Al-Attiyah explained the inherited win had come at a price.

"We tried to set a high pace, but our plan was not having to open tomorrow (Thursday) because there will be no bikes and, therefore, no tracks," he said.

"But, even if we falter a bit tomorrow in these conditions, it will put us in a favourable position for the next day."

The Qatari, seeking a fourth Dakar title behind the wheel of a Toyota, pulled a further 25seconds clear of Sebastien Loeb in the overall car rankings to lead the French rally star by 38mins 05sec.

"We are moving in the right direction day after day," commented Al-Attiyah, whose Dakar titles came driving for three different constructors - Volkswagen in 2011, Mini in 2015 and Toyota four years later. 

Loeb, runner-up in the stage ahead of Carlos Sainz in Audi's new hybrid, had his prospects of overall victory dented on Tuesday after his car's propshaft broke after just 10km.

Wednesday's testing stage, the longest on this year's route, caught out Spain's Nani Roma, winner on two wheels in 2004 and four wheels in 2014, and France's Guerlain Chicherit.

Both walked away unscathed after crashes, their cars turned upside down. 

In the bikes category Spain's Joan Barreda Bort notched up his second stage win in three days -- his 29th career special stage win in the race -- with Chile's Pablo Quintanilla in second.

Rui Goncalves was third to earn his first Dakar podium finish. The 36-year-old Portuguese broke his arm in the run up to last year's debut. 

Briton Sam Sunderland leads the overall standings by three minutes over 2018 winner Matthias Walkner of Austria.

Barreda Bort moved to within 13 minutes of Sunderland in sixth place, shrugging off tendinitis in his arm, the legacy of a crash into rocks on the opening day.

"It's a bit inflamed, but I'll have to cope with it to keep attacking," he said.

"Of course, I'm still in the hunt for a top placing, but I need to take it step by step… one kilometre at a time."

Before Saturday's well-earned rest day in Riyadh come two stages around the Saudi capital.