Top-seed Marin Cilic lost in straight sets to Kei Nishikori of Japan in the quarterfinals Friday 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 in Zagreb, Croatia, and had won nine of 11 matches this year.
Cilic's loss left the tournament without any of its top four seeds in the semi-finals. Second-seed Milos Raonic, third-seed John Isner and fourth-seed Sam Querrey were eliminated by the second round.
Nishikori, the fifth seed, reached his second semi-final of the year. He opened the year 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 Stefanie Voegele of Switzerland, 6-2, 6-4 to return to the finals of the US National Indoor Championships.
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 of her career 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 quarterfinals.
The Erakovic-Lisicki match will mark the final women's tournament held in Memphis. The event, which moved to Memphis in 2002, is moving to Rio de Janeiro in 2013.