Giroud beat Nagoya goalkeeper Seigo Narazaki just three minutes in, converting a cross from Tomas Rosicky to give the visitors an early lead.
Japan coach Alberto Zaccheroni believes upcoming friendlies against France and Brazil will show the Blue Samurai the way to go as he dreams of presenting them as serious contenders at the 2014 World Cup.
Arsenal forward Ryo Miyaichi was among 12 European-based players named to Japan's 25-man squad for three final-round World Cup qualifiers against Oman, Jordan and Australia next month.
Bolton teenage winger Ryo Miyaichi could be in line for his international debut after coach Alberto Zaccheroni named him in Japan's squad for Wednesday's World Cup qualifier against Uzbekistan.
Arsenal's Japanese youngster Ryo Miyaichi has joined Bolton Wanderers in a loan move until the end of the season, it was confirmed on Tuesday.
The rising number of Japanese footballers impressing in European leagues reflects the growing strength of the sport in the Asian region, Arsenal manager Arsene Wenger said on Monday.
Japanese teenage striker Ryo Miyaichi has vowed to become a Premier League success story as he gears up for his upcoming Arsenal debut.
Arsenal manager Arsene Wenger says he wants to obtain a work permit for Japanese winger Ryo Miyaichi.