Tokyo, Japan, 8 October 2016 | AAP

Australian sixth seed Nick Kyrgios is on track for his third title of the year, winning through to the semifinals of the Japan Open with a 6-4 6-2 win over Gilles Muller of Luxembourg.

The world No.15 breezed through to the last four in just 70 minutes on Friday to set up a last-four showdown with French second seed Gael Monfils, who had to fight hard to beat No.7 Ivo Karlovic of Croatia in two tiebreaks.

Resting up after a second-round walkover against Czech Radek Stepanek, Kyrgios laid on a serving spectacle by hammering 18 aces at the Ariake Colosseum.

“I thought I played great today,” Kyrgios said. “I served well, returned well and my engagement level was really good the whole time.”

The Australian holds a 36-14 win-loss record for the season ahead of his sixth semifinal of 2016. He has already won titles this year in Marseille and Atlanta.

Fourth-seeded Croatian Marin Cilic warmed up for next month’s Davis Cup final, crushing Argentina’s Juan Monaco 7-5 6-1 to reach the semifinals to take on Belgian fifth seed David Goffin – a 1-6 7-5 6-2 winner over Joao Sousa of Portugal.

Cilic has boosted his chances of claiming one of the eight spots for the season-ending ATP World Tour Finals, to be played in London in the week before the Davis Cup showdown.

Cilic stands provisionally 10th in the race to London and, by winning the Tokyo title, he can move to ninth in the chase.

“It was a tough first set. I was up a break but I made some unforced errors. It was not easy to hit the ball past him,” Cilic said.

“But after I broke him early in the second set, he was more or less out of the match. That is always a good way to finish it.”

Cilic will have revenge in mind when he plays Goffin, who has beaten him twice this year.

“He’s playing well – I need to take a different approach than in our other matches. My serve was a bit up and down today, so I need to bring my good serve to this match.”