Rublev romps to Hong Kong title to boost Australian Open hopes
The 26-year-old Rublev has reached nine Grand Slam quarter-finals without ever progressing further.
But he must be rated among the favourites for the first major of the year at Melbourne Park after romping to his 15th ATP Tour crown in just 77 minutes.
"The title is something special," said Rublev. "So I couldn't have had a better week.
"Now with a really happy feeling I go to Melbourne. I will enjoy one week of practice there and then we will start the Australian Open."
The last time Rublev lost to a player outside the top 50 was to the 69th-ranked Ruusuvuori, in a three-hour, 16-minute marathon, at the Cincinnati Masters last August.
But that never looked like it might be repeated at Victoria Park.
Both players quickly settled into the final, with some furious hitting off both wings from Ruusuvuori at the baseline being met with more powerful counter-punching from Rublev.
At 3-3, Rublev upped the ante further and, on his fourth break point, nudged ahead with a rasping backhand winner.
Ruusuvuori saved a set point at 4-5 and then created his first and only break point in the match, but it proved in vain as Rublev took the opener in 44 minutes.
The Russian dominated the second set more than the scoreline suggests, barely giving up a point on his own serve while constantly pressuring his 24-year-old opponent.
Rublev broke to love for a 5-4 lead before sealing the championship on his first match point when Ruusuvuori netted.
"Of course this gives me more confidence ahead of the Australian Open," he said.
"Now I have one week to prepare, so we're going to work on my fitness as we have some time but basically keep doing the same."
Rublev became the first men's Hong Kong Open winner for more than two decades on the tournament's return to the city.
The Russian added his name to an illustrious list of former winners that includes all-time greats Rod Laver and Pete Sampras.
Ruusuvuori was playing in only his second ATP Tour final after Pune in 2022 and paid tribute to Rublev at the trophy presentation.
"You're one of the hardest working and toughest competitors, but still one of the nicest guys on tour," said Ruusuvuori.
"I don't think anyone deserves it more than you. Congrats to you and your team.
"We'll keep fighting. I got you once before, but this was your time. I think we're going to have many more fights in the future."