Much of the attention fell on Osaka, though, who was at a loss to explain why she struggled for fluency against her Ukrainian opponent.
Tsurenko held sway in the first hour of the contest on Pat Rafter Arena, skipping clear in both sets after the 2017 champion had worked her way back from an early break. Mostly, it's the expectations.
The world No. 5 made 26 unforced errors in the match, which cost her not only the chance to win the title but also to move up to the No. 3 in world ranking.
Osaka, who announced her withdrawal from the Sydney International next week, said: "If I'm being really frank, I just feel like I had the worst attitude today. I've played some good matches (against Lesia Tsurenko)", Pliskova said after the win.
Serving for the title at 5-4 Sunday, Tsurenko lost 13 straight points.
Osaka kicked the air at one point and dropped her racket to the court after missing another, before visibly questioning how she could be getting it so wrong when her forehand skewed wide on game point.
"I was sulking a bit and there are moments that I tried not to do that".
"I think I just dug deep today, and that's important".
The Czech fifth seed enjoyed the victory alongside Stubbs, who has been in her camp since last August providing a tactical and emotional advantage that Pliskova has praised all week.
Pliskova, of the Czech Republic, credited a similar match in the first round with giving her the confidence to rally.
Tsurenko, the world No. 27, will face former champion Karolina Pliskova or 34th ranked Donna Vekic in the final on Sunday.
Naomi Osaka bows to Ukraine's Lesia Tsurenko in the semifinal.
"Physically and tennis-wise I think it was ideal".
Osaka is having to deal with different expectations now.
"I was just focused on every point and thinking about every shot like it's the most important one". "So that's like an added amount of nerves. I felt I was getting better with the time".
She said after the match that she didn't know how to cope once things started to go against her. "I served well, I returned well - I think that was the key today - and I was moving well, that was fantastic".
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