On his Corsica debut, Skoda Fabia driver Rovanperä stopped the leg 2m55.5s in front of Pieniazek, who lost two minutes having a puncture in SS1.
“We made a few set up changes throughout the day also it is currently quite good – the car is more enjoyable to drive,” said Rovanperä, who is on track to spend the championship lead to Sunday.
Éric Camilli headed a thrilling two dimensional battle in WRC two following a high-value scrap with fellow Frenchman Yoann Bonato.
Camilli, which makes his season debut, won all six stages in a VW Polo GTi to develop a 20sec pillow over French rally winner Bonato’s Citroën c 3.
Ciamin headed a trio of drivers insured by just 6.3sec. Kajetan Kajetanowicz (Polo) put 4.8sec straight back in fifth place, together with Fabio Andolfi (Hyundai) 1.5sec adrift in sixth.
Championship leader Ole Christian Veiby was by SS2, but dropped to eighth in SS3 following a pruning cost him 30sec. He recovered to end the leg in position.
Elsewhere, Pierre-Louis Loubet lost more than two minutes having a puncture in SS3. However, the retirement list were Nil Solans, who crashed in SS3, Simone Tempestini, who stopped in the same stage with suspension damage and Adrien Formaux who ripped two wheels off his Fiesta in ss 4.