Sami Pajari led Rally Croatia after an opening Friday that saw his title-chasing Toyota teammates Elfyn Evans and Oliver Solberg crash out.
Championship leader Evans won the first two stages and then came unstuck in the third when he careered off the road after going too fast into a right-handed curve.
"The corner was a bit tighter than expected and we were way too fast and we went off into the trees, unfortunately," said the Welshman, who was first on the road.
"It is very disappointing. Obviously, it was a strong start and things were going well, but yeah, it didn’t end so well.”
Solberg, eight points behind in the standings after three rounds, lasted only five km before his day was over, the Swede clipping an earth bank and spinning before getting stuck.
“I had a little bit of understeer and we just tapped the rear with a rock face,” he said.
After eight stages, Pajari was 13.7 seconds clear of Hyundai's Thierry Neuville with Toyota's Takamoto Katsuta in third and a further 0.9 behind.
Pajari was fastest on stages four, five and eight – while Belgian Neuville won stages three, six and seven – to secure his career first overnight lead in the world championship. The Finn has yet to win at WRC level.
Saturday features eight more stages and 115km of competitive action.
Rally Croatia, returning after a year's absence with a move from Zagreb to Rijeka on the Adriatic coast, is the first pure asphalt event of the season.