Sebastien Loeb maintained his Rally Finland lead through the first loop of Friday morning stages, but Citroen team-mate Mikko Hirvonen is closing in.
Hirvonen was 3.2 seconds quicker than Loeb on the Jukojarvi stage, bringing the World Rally champion's overall advantage down to 4.4s.
Jari-Matti Latvala started the day sharing second place with Hirvonen, but has continued to struggle for pace and rhythm, dropping 12s away from the lead and falling to fourth overall behind Ford team-mate Petter Solberg.
Mads Ostberg and Thierry Neuville remain in touch with the leaders in fifth and sixth places.
Evgeny Novikov moved up to seventh on the day's opening stage, then crashed out on the next. His M-Sport Ford team-mate Ott Tanak now occupies seventh place, just ahead of Chris Atkinson, who has been slowed slightly by intercom issues.