Nishikori, still on a high after reaching the final of last year's U.S. Open, continued his impressive build-up to this month's Australian Open when he demolished Bernard Tomic 6-0 6-4.

He was joined in the last four by Milos Raonic and Grigor Dimitrov, another two up-and-comers tipped to challenge at the first grand slam of the season.

Raonic rode his booming serve to a 7-6(5) 3-6 7-6(2) win over Australia's Sam Groth to set up a mouth-watering semi-final clash against Nishikori.

Dimitrov made light work of his quarter-final with Martin Klizan, defeating the Slovakian 6-3 6-4 to set up an encounter against either Roger Federer or James Duckworth in the last four.

Raonic and Dimitrov both made the semi-finals at Wimbledon last year and while they stumbled against their more seasoned opponents they, along with Nishikori, have been earmarked as potential grand slam winners this year.

Nishikori took less than an hour to brush past Tomic, who was also tipped for big things after reaching the quarters at Wimbledon as a teenager in 2011.

"There was not a lot I could do," the Australian told reporters. "That's why he's gotten to (number) five in the world and potentially has a big chance of becoming a top-three player this year."

Dimitrov saved two match points in his previous match against Frenchman Jeremy Chardy but the Bulgarian was always in control against Klizan.

Raonic had a tougher workout against Groth, another big server. The towering Canadian served 15 aces but more importantly, he held his composure in the tiebreakers.

"Now we are in the semi-finals of a tournament," Raonic said.

"Everybody that's in that stage is already playing pretty well. They've gotten some matches behind them. Now it just comes down to stepping up."

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