A photo that has gone viral shows that Japan's program left behind a fastidious locker room, along with a note that said "thank you" in Russian and was signed "Japan". After a school day, they clean their classrooms.
"I don't like to have too many days off between games", he said.
However, he refused to look past Japan towards a potential quarter-final against Mexico or Brazil.
Need further proof the Japanese players have the kind of manners that would make your parents want to invite them around for a holiday meal?
Sharing a picture of their spotless post-match dressing room, Janssens wrote: "This is the Japanese dressingroom (sic) after losing to Belgium in the 94' minute".
As dawn broke over the country, during the closing stages of Japan's last 16 match with Belgium in Rostov-on-Don, the Samurai Blue were 2-0 up and on course for their first World Cup quarter-final.
Belgium, 58 places above Japan in Federation Internationale de Football Association rankings, scored a 94th-minute victor resulting in elation or the European side and left the sole Asian surviving side in the World Cup thus far devastated.
"They are not in the World Cup, so now it is time to shine".
This might be the best chance for Belgium's "golden generation" to win a major trophy after being eliminated in the last eight at the 2014 World Cup and Euro 2016.
In Belgium vs Japan match, the former appears to be the clear favourite.
After being released by Milan in the summer of 2017, he joined Mexican giants Pachuca, and according to reports in Japan prior to the World Cup, he will not extend his one year contract that expires later this month.
Croatia also won on penalties, defeating Denmark 3-2 in the shoot-out following another 1-1 draw, with Luka Modric having a spot-kick saved late in extra time.
"Neymar is probably the best player I've ever played with or against".
Sadly, though, that's not how it goes - as Japan knows all too well.