Giroud sent the visitors on their way after just three minutes at a packed Toyota Stadium before Japanese midfielder Ryo Miyaichi got his debut Arsenal goal from the penalty spot. England’s Theo Walcott added a third after half-time before Kisho Yano gave Nagoya reason to cheer with a consolation strike 18 minutes from the end.
“Of course it was a special event with almost a full crowd,” Wenger said afterwards. “I think especially in the first half we played with great fluency, created many chances and the game was very interesting.
“In the second half, we were capable of maintaining the pace but we lost a bit of cohesion. Above all it was a very interesting game.”
Arsenal had scored 14 goals in their games against the Indonesian Dream Team and Vietnam and there was no let-up in front of a record 42,919 fans — many of them red-shirted — in Toyota.
With the action barely underway, Tomas Rosicky supplied the cross as Giroud climbed for a header which he buried past Nagoya goalkeeper Seigo Narazaki.
Wenger deployed Miyaichi from the start and when Marcus Tulio Tanaka handled in the box, the promising youngster buried the spot-kick on 26 minutes for his first Arsenal goal and a 2-0 lead.
Walcott was denied by the ‘keeper’s legs as Arsenal pressed for a third, while Yoshizumi Ogawa nearly reduced the arrears but scuffed his shot harmlessly.
Arsenal resumed their assault after the break but Nagoya came close when their Australia striker Josh Kennedy volleyed over an empty goal under pressure from two defenders.
Walcott repeatedly threatened for Arsenal and he stole in for their third goal — after a sumptuous pass from 16-year-old Gedion Zelalem — with a lifted shot over Nagoya ‘keeper Narazaki.
The night was Arsenal’s but Nagoya were rewarded for their efforts when Kisho Yano planted a firm header past Lukasz Fabianski after a high cross from the right. “We didn’t give up, we tried until the end to score a second goal,” said Nagoya coach Dragan Stojkovic, who played under Wenger at the Japanese club.
“It was a memorable day, a memorable game. Of course, they can go home very satisfied.” Arsenal, hoping to end an eight-year trophy drought this season, now travel to Saitama where they will play Japan’s Urawa Reds on Friday.
Wenger had an 18-month stint as Nagoya manager before joining Arsenal in 1996 and embarking on a run which has yielded three Premier League titles and four FA Cup wins.