In the final, Tsurenko will play fifth-seeded Czech Karolina Pliskova, who beat Croatia's Donna Vekic 6-3, 6-4.
Pliskova won her second Brisbane title on Sunday, over-running Lesia Tsurenko 4-6 7-5 6-2 after being just two points from defeat.
Medvedev saved four break points to take a 3-2 lead in the second set before dragging the match into a decider but his opponent, who lost their previous meeting in last year's Tokyo final, was not to be denied again.
Tsurenko will at least have the opportunity to seal swift revenge, with the duo paired in the Sydney International first round next week as they gear up for the Australian Open.
After the match, Osaka made a decision to withdraw from the super strong Sydney International where she should have been the third seed behind Simona Halep and Angelique Kerber, deciding to take a week off and reset her game before the start of the Australian Open where she is among the favorites for the title.
It's going to be tough (in the final).
However, the former world No.1 - spurred on by her Australian coach Rennae Stubbs - rose to the challenge in spectacular fashion.
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The German added: "We only scored more goals , but the possession was at least 60:40 for them in all the games but we won them". Like all the boys who don't play constantly week in week out, they kept the level really high in training.
"I don't know, maybe she raised her level so much that I was not ready for that".
"But then the ball wouldn't go in and then I would go back to being like childish and stuff".
"I feel better with my serve and that I am moving well", she said.
But the 2017 Brisbane champion said she preferred that to being the underdog.
"I've been in this situation many times, so I don't feel any pressure that I'm the seeded one that I have to win", Pliskova said.
"I think everything was against me today".
The final point of the match came as Tsurenko was 15-40 down, and the 29-year hit a forehand into the net to give Pliskova the title in Brisbane.
"I don't want to say that this was my best tennis, but it was quite a high level", Tsurenko said.