Welshman Evans won two of the four forest stages, and was second in the others, to lead Hyundai's Tanak by 8.5 seconds.
"The feeling with the car has been really good and we can’t complain with a day like that," said the leader. "It's good but we have to do it all again tomorrow. Who knows what the conditions will be like."
The rally, which crosses over into Norway, has been shortened this year due to an unusually mild winter and a lack of snow.
Some snow fell on Friday, however, with temperatures plunging overnight.
Tanak said he was taking it step-by-step.
"I want to spend as much time in the car as possible and today was quite short, but lots has been learned," said the Estonian.
Finnish teenager Kalle Rovanpera was third in a Toyota, with six times world champion Sebastien Ogier making it three in the top four for the Japanese manufacturer.
Hyundai's Monte Carlo winner and championship leader Thierry Neuville was sixth after the disadvantage of having to run first on the road.
"This morning, the layer of ice was very thin in places and the gravel was coming out, which gives more grip to the cars behind," said the Belgian.
"This rally is so short, it won’t be possible to catch up a lot of time, but we will fight hard and see what we can achieve tomorrow." (Reporting by Alan Baldwin in London, editing by Ken Ferris)