Ford's Marcus Gronholm extended his Finnish rally lead to 4.4 seconds over fellow Finn Mikko Hirvonen after winning the Killeri second stage.
Citroen's world champion Sebastien Loeb of France finished the day in third place, a further 15.8sec behind.
World championship leader Gronholm, almost unbeatable on his homesoil forest tracks, having won the race for the last three years, traded the lead yesterday with team-mate Hirvonen but never looked back after regaining it on the fifth stage.
After being tied for first place at the sixth stage with Hirvonen, Gronholm swept through the remaining stages, clinching eight of the day's 10 stages.
"For Ford, it has been a great day," Gronholm said. "The new car is good, Mikko is fast and we are leading."
Gronholm was confident he could improve on his lead overnight because he knows the majority of the roads. "Being the first on the road today was not the best," he said.
"Tomorrow will be better for me, I know the roads more."
The Finn ended with a total time of one hour, 5min 18.5sec after 11 stages. The Rally's Killeri superspecial stage was held on Thursday.
"I tried all day but the Fords were too fast," said Loeb, the triple world champion who is 20.2sec behind Gronholm.
"I don't know what the plan is tomorrow but we have to keep pushing. The problem is that the Subarus are not too far behind. We have to keep pushing or they will come back into contention."
Subaru's Australian driver Chris Atkinson is fourth, 26.7sec behind Loeb with Norwegian team mate Petter Solberg in fifth place a further 10.4sec behind.
