While Latvala's Volkswagen team-mate and World Rally Championship title rival Sebastien Ogier was swiftly able to retake second from Kris Meeke's Citroen, the champion still had no answer to the home favourite.
Kubica and Ogier quiz each other
Latvala won three of Saturday morning's five stages and led Ogier by 29.9 seconds before heading for service.
Meeke tipped for 2015 Finland win
Meeke stayed in touch with Ogier for second until a small mistake on the Himos stage cost him several seconds. He is now 13.5s behind Ogier and focusing on ensuring a podium finish.
There is still a 36s gap from Meeke back to fourth-placed Andreas Mikkelsen, who stretched away from Mads Ostberg and Mikko Hirvonen through the morning.
Further back, the recovering Juho Hanninen has now taken eighth from Elfyn Evans and setting his sights on the half-minute gap to Hyundai team-mate Hayden Paddon in seventh.
Robert Kubica rejoined for leg two in his repaired M-Sport Ford following Friday morning's crash, but his Rally2 penalties mean he is only just in the top 50 overall.
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Latvala wins in Finland to trim Ogier's championship lead
Latvala claims home win in Finland
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