Top-seed Marin Cilic lost in straight sets to Japan’s Kei Nishikori on Friday in the quarter-finals of the US National Indoor Tennis Championships.

Nishikori’s 6-2 6-2 victory denied Cilic an opportunity to win back-to-back ATP World Tour titles. Cilic claimed his ninth career title two weeks ago at Zagreb in Croatia and had won nine of 11 matches this year.

Cilic’s loss leaves the tournament without its top four seeds in the semi-finals. Second-seed Milos Raonic, third-ranked John Isner and fourth-seed Sam Querrey were eliminated by the second round.

Nishikori, the No.5 seed, reached his second semi-final of the year. He opened 2013 by reaching the same round in Brisbane.

Nishikori played nearly flawless tennis after breaking Cilic to go up 3-2 in the first set. He broke Cilic twice in the second set to take a 4-1 lead and did not face a break point. Nishikori smashed a forehand winner on match point to advance.

In women’s play, Marina Erakovic of New Zealand defeated Switzerland’s Stefanie Voegele 6-2 6-4 to return to the finals of the indoor event.

Erakovic, the world’s 71st-ranked player, will play German Sabine Lisicki on Saturday for the championship. Lisicki, ranked 40th, beat No.7 seed Magdalena Rybarikova of Slovakia 7-5 7-5.

Erakovic is seeking the first WTA title after reaching two finals, last year in Memphis and 2011 in Quebec.

Lisicki, the No.3 seed, is playing in Memphis for the first time since 2009 when she reached the quarter-finals.

The Erakovic-Lisicki match will mark the final women’s tournament held in Memphis. The event, which moved to the city in 2002, is shifting to Rio de Janeiro in 2013.