With second-placed Dani Sordo electing to play it safe in the rough terrain and guarantee a runner-up spot, Latvala was able to pull comfortably clear without pushing too hard.
The Volkswagen and Citroen will go into Sunday's decisive four stages separated by 1m04s.
Thierry Neuville retains third in the best of the M-Sport Fords, having also opted for a conservative approach.
His team-mate Nasser Al-Attiyah continues to resist Andreas Mikkelsen for fourth.
Every time the Norwegian has got close, either Al-Attiyah has raised his pace or Mikkelsen has hit problems, including a puncture on the day's final stage.
Mads Ostberg is now up to sixth, but Mikko Hirvonen's recovery has been stymied by further issues, including a puncture and a broken wheel. He is eighth.
Erstwhile runaway leader Evgeny Novikov won two stages on Saturday afternoon as he got back up to ninth place.
Sebastien Ogier is also back in the points after his Friday problems. He got ahead of WRC 2 leader Robert Kubica for 10th overall on SS10.