The 29-year-old gave his French opponent no chance as he put on a commanding all court display to advance to the final for the second time in three years.
Nishikori had not won a tournament since Memphis in 2016, and was hampered by a wrist injury the following year which forced a break from the 2018 tour. "I served well, I returned well - I think that was the key today - and I was moving well, that was fantastic".
Regardless of whether he choses to play in Sydney or not, Medvedev leaves Brisbane with strong preparation behind him for the Australian Open.More news: Clemson overwhelms Alabama to claim second national title in three years
"I think today was probably one of the most flawless matches I've ever played in my career", said Vekic. "But then the ball wouldn't go in, and then I would go back to being like childish and stuff", Osaka said.
But the 22-year-old Russian responded by capitalising on his first opportunity to secure a break in the match in the second game of the next set.
The Frenchman pounced in the ninth game, drilling big winners from both wings to grab the decisive break and serve out the set in 42 minutes.
· Karolina Pliskova won her second Brisbane title, coming back from a set and 5-3 down in the second set to beat Lesia Tsurenko, 4-6, 7-5, 6-2.More news: Canadian Bianca Andreescu heading to ASB Classic finals
But he chalked it up as another valuable lesson against a red-hot opponent as he prepares for next week's Sydney International, where he made the final a year ago, and the Australian Open later this month.
"So I had to start at some ATP Challenger Tour events", said Nishikori. He served out the set to level the match, 6-3.
"Everything was going well for me". So I think that was my main problem.
"I was a bit more aggressive than him and it made the difference", he said. "Hopefully this isn't like a recurring thing".More news: Dick Cheney's daughter slams Christian Bale's 'Satan' comment — Golden Globes
But the smile on the Japanese world number nine's face while holding the Brisbane International trophy aloft told just how important the victory was.