Spain's Carlos Sainz toppled compatriot Nani Roma from top spot on stage four of the car category at the Dakar Rally in Argentina, while Joan Barreda Bort's advantage on two wheels slashed to just three minutes by former champion Marc Coma in another Spanish duel.
The bikes and quads faced a 352 kilometre (219 mile) timed section and defending champion in the motorbike category Cyril Despres of France and Coma had contrasting days.
Despres could only manage 16th on the stage, crossing the finish line more than 42 minutes down on the day's winner.
The Frenchman slipped down to sixth place overall, but is now a massive 41 minutes and 17 seconds off the lead - his chances of winning a third straight title and sixth in total are fading fast.
Coma, a three-time winner of this event, closed to within three minutes and ten seconds of Barreda Bort with a third place finish on Wednesday.
In the car category, Qatar's Nasser Al Attiyah dominated the first phase and reached the end of the first sector in two hours 12 minutes and 37 seconds, 33 seconds quicker than Sainz.
Overnight leader Roma came in fourth, behind Argentina's Orlando Terranova, more than three minutes in arrears.
However, the run to the finish turned into a duel between 11-time champion Stephane Peterhansel, who looked back to his best, and Sainz.
The pair overtook each other several times before Sainz stormed the last 50 kilometres, crossing the line in five hours, 20 minutes 32 seconds, more than six minutes ahead of Peterhansel.
Al Attiyah was third fastest, nine minutes behind Sainz, with Argentina's Federico Villagra fourth.
Roma could only manage fifth, conceding more than fourteen minutes to Sainz, and lost first place in the overall standings as a result.
Stage five will take the competitors from Chilecito to Tucuman on a 527 kilometre (327.5 mile) course, the same for all the Dakar disciplines this time.