Novak Djokovic upset by Kei Nishikori in U.S. Open semifinals

Novak Djokovic, the top-ranked player in the world, was upset by No. 10 Kei Nishikori in the semifinals of the U.S. Open on Saturday. Nishikori won in four

Novak Djokovic, the top-ranked player in the world, was upset by No. 10 Kei Nishikori in the semifinals of the U.S. Open on Saturday.

Nishikori won in four sets: 6-4, 1-6, 7-6, 6-3. The 24-year-old will face the winner of the semifinal betwen No. 2 Roger Feder and No. 14 Marin Cilic.

This marks the first time a Japanese man has advanced to the Finals of a Grand Slam tournament. 

Nishikori turned pro in 2007.

U.S. Open Live Blog: Marin Cilic vs. Roger Federer live scores, updates

- Chris Johnson