Karolina Pliskova has used her big serve to full effect to ease to a 6-4 6-4 victory over home favourite and US Open champion Naomi Osaka in the Pan Pacific Open final in Tokyo.

Osaka, in top form going into Sunday's contest on the back of 10 consecutive wins, appeared uncertain throughout the match as her Czech opponent broke serve once in each set to triumph in 64 minutes.

Before the final, Pliskova had spent 419 minutes on court, more than any other player and almost twice as long as Osaka, but the Japanese player soon wilted and was unable to match the brilliance that secured her a first grand slam title.

Pliskova, meanwhile, was more than happy to take advantage of Osaka's sloppiness, converting her break point opportunities and reeling off the last 11 points to secure a second WTA title of the campaign.

"It was important for me to play just two sets and not go to a third one. I needed a match like this," the 26-year-old world No.8 told reporters.

"Also, confidence gets higher and higher with every match that you win and I won a lot of tough matches here, a lot of tough sets against tough opponents, so I'm proud of this."

Osaka's defeat was her second in the tournament final, having also been runner-up in 2016, as the 20-year-old seemed to finally succumb to the after-effects of her emotional US Open triumph earlier this month.

"I have literally never been so tired in my entire life," she told reporters.

"I haven't really had much time to rest, so I feel tired right now."

She can still, however, take heart from her recent run of form as she looks to finish the year on a strong note.

"To play the final of the US Open and then to come here, I think I did pretty well," Osaka said.

In clinching the title, Pliskova took a big step towards securing her spot at the season-ending WTA Finals in Singapore, the victory putting her just ahead of Kiki Bertens for the eighth and final berth in next month's field.