Defending champion Kei Nishikori rallied past Russian Mikhail Bogomolov Jr. 3-6, 6-3, 6-2 Friday in the quarterfinals of the U.S. National Indoor Tennis Championships.

The top-seeded Nishikori reached his second semifinal this year, despite trailing 5-0 and dropping the first set.

Bogomolov broke Nishikori for a 3-2 lead in the second set only to be broken on his next two serves, and Nishikori served out to take the set. In the third, Nishikori fought off three break points to hold serve and broke Bogomolov in consecutive games to take a 5-2 lead.

Nishikori will play either third-seeded Australian Lleyton Hewitt or American Michael Russell on Saturday. American Jack Sock will play Ivo Karlovic of Croatia on Friday night.