Japan will come up against Colombia, Greece and Ivory Coast in Group C at the World Cup finals in Brazil, though first thing on the agenda is an international friendly at Saitama Stadium.
Zaccheroni named 12 European-based players in his 23-man squad for the showpiece event, with Keisuke Honda (Milan), Shinji Kagawa (Manchester United) and Shinji Okazaki (Mainz) headlining the selections.
Okubo's selection was questioned despite topping the J.League charts last season with 27 goals, while he has already netted eight this campaign.
The 31-year-old will also take confidence from Zaccheroni's comments at Japan's squad announcement almost a fortnight ago.
"The real surprise should be that he has chosen Kagawa, who scored no goals in the Premier League, and (Yoichiro) Kakitani, who's scored just once so far in the J. League," said the Italian.
"If this was a country like Brazil, Kagawa and Kakitani would not have been picked. And if they were, there would be a storm of boos."
Tuesday's clash is the first of three games before the World Cup, with matches against Costa Rica and Zambia set to follow during Japan's training camp in Florida.
