Japan's fifth-ranked Kei Nishikori and Croatia's eighth-ranked Marin Cilic will meet in a rematch of last year's US Open final after advancing to the ATP and WTA Washington Open semi-finals.

And Nishikori made it clear he seeks a measure of revenge Saturday for Cilic denying his bid to become the first Asian man to win a Grand Slam title.

"It's going to be great motivation for me," Nishikori said. "I think it's going to be very interesting."

Reigning US Open champion Cilic defeated German teen Alexander Zverev 7-5, 7-6 (7/3) while Nishikori, the top remaining seed after Britain's Andy Murray crashed out, ousted Australia's Sam Groth 6-4, 6-4 in quarter-final matches.

That set up their first meeting since Cilic downed Nishikori 6-3, 6-3, 6-3, at Arthur Ashe Stadium in September for his first Grand Slam crown.

"To play Kei again is for sure going to be an entertaining and exciting match," Cilic said. "I wouldn't say I'm at the same form as I was at the US Open. Emotion-wise, it's going to be extremely different. Before the Slam final we were both nervous.

"For sure I'm going to take some things out of that match to get the win."

Nishikori, who has a 5-3 edge on Cilic in their all-time rivalry, said he recalls not being at his best for the biggest moment of his career thus far and welcomes another chance at the man who frustrated his dream.

"I was really nervous and I wasn't really into the match," Nishikori said. "Physically I wasn't 100 percent.

"I'm a better player than last year. I'm a little more solid baseline player. I'm a more aggressive player than before. I think I'm getting better. It's going to be a good match."

US eighth seed John Isner, coming off his 10th career title last week in Atlanta, fired 20 aces in a 6-3, 5-7, 6-3 win over Lithuania's Ricardas Berankis to grab a spot in the other semi-final against compatriot Steve Johnson, who beat American Jack Sock 7-6 (7/5), 6-1.

- Not easy for Nishikori -

Nishikori, 25, chases his third title of 2015 after Memphis and Barcelona and the 10th of his career.

Nishikori took advantage of his fifth break chance in the seventh game, grabbing a 4-3 lead when Groth hit a forehand drop volley wide, and held twice more for the first set.

Groth, ranked a career-best 62nd, double faulted to gift Nishikori a break for a 3-2 edge in the second. Nishikori denied Groth on two break points in the eighth game and held at love to end matters after 86 minutes.

"It wasn't easy," Nishikori said. "He has a great serve. It's never easy to face someone new but I thought I handled it well."

Cilic, 26, broke in the last game of the first set and the second game of the second set and served for the match before Zverev broke back. Cilic took the last three points of the tie-breaker, reaching only his second semi-final of the year when Zverev netted a forehand.

"Luckily I played solid at the end," Cilic said.

On the women's side, Australian second seed Samantha Stosur advanced 4-0 when Romania's Monica Niculescu retired with a left abdominal strain. Stosur plays American Sloane Stephens next in a shock 10-match win run for the Aussie after a July clay title in Austria.

"Probably a little bit surprised," Stosur said. "Started hitting on hardcourts last Thursday. Didn't feel ready to play in a lot of ways. I've been able to adapt really well."

Russian top seed Ekaterina Makarova plays compatriot Anastasia Pavlyuchenkova in the other semi-final.
Source: AFP