Memphis - Fifth-seeded Kei Nishikori of Japan cruised past top-seeded Marin Cilic 6-4, 6-2 on Friday to reach the semi-finals of the US National Indoor Tennis Championships.
Croatia's Cilic had saved three match points in his previous match against Igor Sijsling, but could not find the answer against Nishikori, who had just four aces compared to a dozen for Cilic but won 69 percent of points on his serve.
"I was dominating with my serve," said the 23-year-old Nishikori, who also reached the semi-finals in Brisbane in January but retired from that match against Andy Murray with a knee injury.
Since then, he has reached the fourth round of the Australian Open.
"It's getting better every match... little by little," Nishikori said of his game.
He next faces Australian Marinko Matosevic, a 6-7 (6/8), 6-2, 6-4 winner over seventh-seeded Alexandr Dolgopolov of Ukraine.
Nishikori won their only prior meeting at Brisbane earlier this year.
The other men's semi-final in this combined ATP and WTA event will pit Spain's Feliciano Lopez against Uzbekistan's Denis Istomin.
Lopez defeated US wildcard Jack Sock 6-4, 6-3, and Istoman was a 6-4, 7-6 (7/5) winner over Michael Russell of the United States.
Results on Friday from the $1.58 million ATP and WTA US Indoor Championships (x denotes seed):
Quarter-finalsKei Nishikori (JPN x5) bt Marin Cilic (CRO x1) 6-4, 6-2
Marinko Matosevic (AUS) bt Alexandr Dolgopolov (UKR x7) 6-7 (6/8), 6-2, 6-4
Feliciano Lopez (ESP) bt Jack Sock (USA) 6-4, 6-3
Denis Istomin (UZB) bt Michael Russell (USA) 6-4, 7-6 (7/5)