Nagashima's Giants won championships in 1994, 1996 and 2000, and he managed the team until 2001. For the 2000 Japan Series, Nagashima was managing against his former teammate, Sadaharu Oh, who was the manager for the Fukuoka Daiei Hawks. The press called it the O-N Series. In 2002, it was announced that he would lead the Japanese Olympic baseball team. The team (consisting entirely of players from the Japanese professional leagues) beat China, Taiwan, and Korea to win the Asia tournament in November 2003, but Nagashima suffered a stroke in March 2004, and was unable to travel to the Athens Olympics. The team ended up with a bronze medal in the Olympics after losing to Australia.