Finland's Jari-Matti Latvala took over the lead from Frenchman Sebastien Loeb following the six special stages on the third and penultimate day of the season-closing Wales Rally GB.
Loeb, who secured his record eighth consecutive world title on Friday when sole rival Mikko Hirvonen abandoned, was second at six seconds after stages 12 to 17.
Norwegian Mads Ostberg, who has been suffering from engine problems, did well to end up third but at nearly three minutes off the pace the fight for the last race of the season has come down to a duel between Latvala and Loeb.
The Frenchman had started the first three stages on Saturday just 1.1 secs ahead of his Finnish rival and extended his advantage to just over seven seconds by the end of that session.
Latvala, however, launched a determined fightback during which he powered his Ford Fiesta to the fastest times in the closing stages of the afternoon (SS 15-17).
"It's going really well and tomorrow (Sunday) morning I need to wake up with a very clean head," said Latvala, who has four rally wins to his name but is yet to win this season.
"I have good confidence and I'm so hungry for the victory."
Loeb said his progress had been slowed by the slippery conditions he encountered by having to run at the head of the field.
"I was pushing very hard but honestly it was so slippery and I had absolutely no grip," said the Frenchman.
"I tried and made no mistake but I could not do any better."
Sunday will feature the final six stages of the Wales Rally GB, the 13th and final race in the world rally championship.