His homeland was hit by one of the strongest earthquakes of all time on Friday morning and it sparked a deadly tsunami.
"It was terrifying and I was distraught," explained Nagatomo after a 1-1 draw at Brescia.
"Even before the game I felt my head spinning, as I kept thinking back to what was happening in Japan.
"At the starting whistle, I managed to put aside those ugly thoughts and concentrate on the game.
"The good thing about being a professional football player is that it's my duty to do my best and in that way reassure my people.
"I spoke to my family and thankfully they are alright."