Osaka has never lost at a major once reaching the q/final stage.
I think this will have a lot to do with both ladies 1st serves,Vika can neutralize a big server,though Vika's 2nd serve has always been her weakness.Both ladies have good bhands,Vika to me has a slightly better one,Osaka has a better fhand.
Both ladies can redirect,though I feel Osaka can absorb pace better.
My heart says Vika,
My head says Osaka in 3 sets.
BTW If Vika wins she will rise to No11 ranking in the world.If she loses No 14 ranking in the world
If Vika wins today,she will have the longest gap between Grand Slam women's singles titles in Open Era history,7 years,231 days.
Vika last win AO 2013.
Regardless of the result if Osaka wins she will remain at No 4 world ranking.