Spadea's fellow American, eighth-seed Mardy Fish dropped a set against Lee Hyung-taik of South Korea before winning 6-4 3-6 6-1.
BBC: Alex Bogdanovic, British tennis player
2.
Federer faces 10th seed Tim Henman in Sunday's final after the former British number one beat South Korea's Lee Hyung-taik 6-4 7-6 in the other semifinal.
CNN: Federer and Henman in Tokyo final
3.
The pair will meet in round two after Bogdanovic beat former semi-finalist Hyung-Taik Lee 6-4 6-4, and Baker saw off Alexander Peya 3-6 7-6 (7-5) 6-3.